GI News is published online every month by the
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that are digested at a rate that our bodies can comfortably accommodate
and to share the latest scientific findings on food and diet with a
particular focus on carbohydrates, dietary fibres, blood glucose and the
glycemic index.
Publisher: Professor Jennie Brand-Miller, AM, PhD, FAIFST, FNSA
Editor: Philippa Sandall
Scientific Editor/Managing Editor: Alan Barclay, PhD, APD, AN
Contact GI News: glycemic.index@gmail.com
Sydney University Glycemic Index Research Service
Manager: Fiona Atkinson, PhD, APD, AN
Contact: sugirs.manager@sydney.edu.au
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1 September 2019
GI News - September 2019
FOOD FOR THOUGHT
4 STEPS TO BETTER BGLs FOR POTATO LOVERS
STEP 1: KEEP PORTIONS MODERATE. Why? Potatoes are carb
rich. A typical medium potato (150g/5oz) has around 20g carbohydrate to
help power your day. They are what we call good carbs – they put a lot
of really good stuff on your dinner plate like dietary fibre and
essential micronutrients including vitamins C, B (B6, riboflavin,
thiamin and folate) and the minerals potassium, magnesium, and iron. The
easiest way to keep an eye on portion size, is to eyeball the serving
sizes by dividing the dinner plate into three sections. Protein foods
(1) and wholegrains/starchy foods (2) should each take up just a quarter
of the plate. Cooked green veggies or salad veggies (or both) should
fill the remaining half (3).
STEP 2: CHOOSE A LOWER CARB POTATO. There are some
varieties of potato with fewer carbs. We sourced five packaged brands
with about 20–25% less carbohydrate than regular spuds. Because growing
conditions affect the carb content, the producers test their spuds
regularly to ensure they meet the lower carbs claim on the packaging.
Catherine Saxelby at Foodwatch did some experimenting with
Carisma and Spud Lite and reports they are good all-rounders for family
fare: they boil, mash and bake nicely. Check out her reports on her
website (see Read More). If you want to taste test: the team at
GiLicious have shared a recipe with us which you can find in The Good
Carbs Kitchen.
STEP 3: CHOOSE A LOWER GI POTATO. Most
potatoes have high GI values averaging around 77 (globally). This is
because whatever the variety, potato starch consists of amylopectin and
amylose in a fairly constant ratio of 3:1. When we checked the database
at www.glycemicindex.com;
flicked through The Shopper’s Guide to GI Values, and trawled back
issues of GI News we found one potato with a low GI and several with
moderate values which are better choices for managing blood glucose.
While the variety makes a difference, there are other factors
that affect GI. Small, new season potatoes tend to have a lower GI than
fully grown spuds left in the ground longer. The recipe changes things,
too. Cooking spuds in their skins and serving them with a vinegary
dressing lowers the GI. Mashing them with white beans does too as will
letting them get cold and making a potato salad, thanks to the resistant
starch factor. However, it doesn’t seem to make that much difference to
the GI whether you bake, boil or mash a particular variety of potato.
STEP 4: WATCH THE GLYCEMIC LOAD. How
high your blood glucose level rises and how long it remains elevated
when you eat a food or meal containing carbohydrate depends on both the
GI of the carbohydrate and the total amount of carbohydrate in the food
or meal. We use the term “glycemic load” or GL to describe this total
amount. You calculate GL by multiplying the GI of a food by its
available carbohydrate content (carbohydrate minus fibre in the USA) in
the serving (in grams), divided by 100 (because GI is a percentage).
A
regular medium-sized (150g/5oz) boiled potato with a high GI (average
77) provides approximately 20g of available carbohydrate. Its glycemic
load is 15 (77 ÷ 100 × 20 = 15). Eat two potatoes and that jumps to 30.
You
can reduce the load by reducing the portion size of the potato, or by
choosing potatoes with less carbohydrate, or potatoes with a low or
lower GI.
- A medium GiLicious potato which has a moderate GI (61) contains 15 grams of available carbohydrate. Its glycemic load is 9 (61 × 15 ÷ 100 = 9).
- A medium Nadine potato, which has a low GI (49) contains 20 grams of available carbohydrate. Its glycemic load is 10 (49 × 20 ÷ 100 = 10).
Read More:
WHAT’S NEW?
THE KETOGENIC DIET FOR OBESITY AND DIABETES
ConscienHealth’s
Ted Kyle reports on a meta-analysis of ketogenic diets for obesity in
JAMA Internal Medicine that suggests that currently enthusiasm is
outpacing the evidence. Shivam Joshi, Robert Ostfeld, and Michelle
McMacken tell us: “Although the ketogenic diet has garnered much
attention for the dietary treatment of chronic diseases such as obesity
and type 2 diabetes, the evidence supporting its use is currently
limited and the diet’s potential risks are real. Physicians and patients
should continue to judiciously appraise the benefits and risks of the
ketogenic diet in accordance with the evidence, not the hype.”
In the short term, a ketogenic diet can be quite impressive for
weight loss. People have less hunger, eat less, and lose more weight.
However, the long-term results are not nearly so impressive.
Meta-analysis of data from studies that lasted more than a year shows a
difference of less than a kilo versus lower fat diets. This is a case
where statistical significance is clinically insignificant.
Likewise,
we’ve seen sensational results in short-term studies of ketogenic diets
in type 2 diabetes. But if you look at longer-term studies, the results
are bland. Once again, a meta-analysis shows no difference in glycemic
control.
Joshi et al point out that long-term risks
merit your consideration. People report fatigue with keto diets that may
be more annoying than anything. But other issues, including nutritional
deficiencies, are possible. However, the most significant issue, they
say, may come from limiting whole grains, fruits, and legumes in a
person’s diet over the long term. Whole grains offer benefits for
reducing the risk of cardiovascular disease, cancer, and mortality.
Fruits and legumes are also quite beneficial.
It might
be a good thing that keto diets are tough to maintain for the long term.
Banishing beneficial foods from your diet is not something to do
lightly, based solely on short-term benefits.
Read more:
PRODUCT REVIEW
7 LOW CARB GOOD CARBS
We dipped into our book, The Good Carbs Cookbook, to share 7 low carb good carbs to put on the dinner plate.
BEETROOT. Its vibrant colours come from its betalain
pigments – betacyanin in red
purple beetroots, betaxanthin in golden and orange beets. A medium raw
beetroot (about 90g or 3oz) has about 165 kilojoules (40 calories), 2g
protein, no fat, 7g carbs (7g sugars), 3g fibre, 45mg sodium, 240mg
potassium, and a moderate GI (64) when cooked/canned; the GL is low (4).
CAPSICUM.
Red, orange, yellow, green, purple: capsicum’s crisp, juicy flesh sets
the taste bar high. It’s no wonder they have made themselves at home in
kitchens around the world sliced or diced into salads, or stuffed, stir
fried, and roasted. A medium raw capsicum (about 90g or 3oz) has about
80 kilojoules (19 calories), 1.5g protein, 0g fat, 3g carbs (3g sugars),
1g fibre, 2mg sodium, 135mg potassium and a low GI and GL (estimated).
CARROTS.
While its colour is eye-catching, it’s the sweetness that makes it
popular raw and cooked as a crunchy snack or side dish, and in salads,
soups, stir-fries, bakes and roasts. A medium-sized raw carrot (about
130g or 4½oz) has about 170 kilojoules (41 calories), 1g protein, no
fat, 6g carbs (6g sugars), 5g fibre, 49mg sodium, 348mg potassium, and a
low GI (39); the GL is low (2).
CELERIAC.
Knobbly celeriac or celery root may not be one of the best-looking
vegetables around, but it pays to get under its skin. Look for the
smoothest skinned ones to make peeling easier and have a bowl of
acidulated water on hand to help prevent discoloration as the flesh
darkens once cut. A cup of grated celeriac (about 155g or 5½oz) has
about 250 kilojoules (60 calories), 2.5g protein, no fat, 4g carbs (4 g
sugars), 8g fibre, 33mg sodium, 686mg potassium and a low GI and GL
(estimated).
EGGPLANT (AUBERGINE). The rich
meaty flesh of this gorgeous, glossy, deep-tasting veg transforms into a
wonderfully silky texture when pan fried, oven roasted, stuffed, mashed
or pureed. A small raw eggplant (about 320g or 11oz) has about 295
kilojoules (70 calories), 3.5g protein, 1g fat, 8g carbs (8g sugars), 8g
fibre, 16mg sodium, 540mg potassium and a low GI and GL (estimated).
ONIONS.
Just about indispensable, onions are used on a daily basis in sauces,
soups, salads, stews, stir-fries and roasts. They are one of the
earliest cultivated vegetables. 1 medium raw onion (about 90g or 3oz)
has about 130 kilojoules (30 calories), 1.5g protein, 0g fat, 5.5g carbs
(4g sugars and 1.5g starch), 1.5g fibre, 12mg sodium, 124mg potassium,
and a low GI and GL (estimated).
PUMPKIN. Boil
and steam for a quick side dish or soup, but roast when you want
concentrated flavour and creamy sweetness. Toss some seeds on the
compost and bingo, you’ll find yourself with a pumpkin patch. A cup of
raw diced pumpkin (about 120g or 4oz) has about 200 kilojoules (48
calories), 2.5g protein, 0.5g fat, 8g carbs (5g sugars/3g starches),
1.5g fibre, 1mg sodium, 414mg potassium, and a moderate GI (66) when
cooked; the GL is low (5).
Read more:
PERSPECTIVES WITH DR ALAN BARCLAY
REDUCE GLYCEMIC LOAD AND REDUCE TYPE 2 DIABETES RISK
The glycemic index, or GI, is an inherent property of carbohydrate-containing foods and beverages. It is a relative ranking from 0–100, describing the rate and extent to which available carbohydrate (total carbohydrate minus dietary fibre) is digested, absorbed and metabolised into glucose and released into the blood.
Glycemic index testing follows an international standard. Volunteers who have fasted overnight are given 50g of glucose in water as a reference food, and researchers measure their blood samples at eight intervals over a two-hour period. The data enables the researchers to plot a curve, where area under the curve (AUC) is set at 100. On a separate day, the volunteers fast overnight again, and are then given the test food containing 50g of available carbohydrate. The AUC of the test food is expressed as a ratio of that of the glucose reference and is used to calculate the GI value which is a percentage.
Low GI foods (55 and under) are characterised by a slower and lower rise in blood glucose levels. High GI foods (70 and over) are characterised by a faster and higher rise and fall in blood glucose levels.
But speed of digestion is only one part of the story. Quantity counts. How high blood glucose actually rises and how long it remains high after we eat a meal containing carbohydrate foods depends on both the amount of carbohydrate in a food or drink as well as its glycemic index. Researchers from Harvard University and the University of Toronto came up with a term to describe this “speed/quantity” combo: glycemic load (GL). It is calculated by multiplying the GI of a food by the available carbohydrate content (carbohydrates minus fiber) in the serving (expressed in grams), divided by 100 (because GI is a percentage). (GL = GI/100 x available carbs per serving.)
For example, a typical medium-size apple has a glycemic index of 38 and contains 15 grams of available carbohydrate. Therefore, its glycemic load is 38÷ 100 × 15 = 6. If you are hungry, and the apples are particularly crispy, juicy, and delicious, and you eat two, the overall glycemic load of this snack is 12. If you have three, it’s 18.
One unit of glycemic load is equivalent to 1 gram of pure glucose. High GL foods and beverages have a GL value of 20 and above; medium GL foods and beverages have a GL value between 11 and 19; and low GL foods and beverages have a GL value of 10 and under.
What does this all mean for our health and wellbeing? The higher the glycemic load of a food or meal, the more insulin your pancreas needs to produce to drive the glucose into your cells. When we are young, our pancreas is able to produce enough insulin to cover the requirements of high-glycemic load foods and meals, but as we get older, it may no longer be able to cope with higher insulin requirements. This is when type 2 diabetes and other “lifestyle” diseases can start to develop.
In population studies, the GL simultaneously assesses the effect of available carbohydrate and GI on the risk of type 2 diabetes. GI and GL are calculated for the whole diet and adjusted for energy (kilojoules or calories) to help reduce confounding (e.g., the larger a person the more energy they require to maintain their body weight). Around the world, the average adult consumes around 2000 calories (8400 kilojoules) each day, so this is commonly used as the standard comparator.
The most recent systematic review and meta-analysis of population studies found that people consuming a diet with an average GI of 76 have an 87% higher risk of developing diabetes than people consuming a diet with an average dietary GI of 48. The simplest way to reduce average dietary GI is to replace high GI foods and beverages with lower GI alternatives within a particular food group.
Similarly, the recent systematic review and meta-analysis found people consuming a diet with a GL of 257g per 2000 calories have an 89% higher risk of developing diabetes than people consuming a diet with a GL of 73g per 2000 calories.
Because GL is the product of GI and available carbohydrate, you can reduce it by either consuming a low GI diet (e.g., aim for an average GI less than 48), or by consuming less available carbohydrate (e.g., aim for between 130–230 grams per day if you consume 2000 calories (8400 kilojoules) per day), or both.
For example, for people who typically consume a relatively high carbohydrate diet (e.g., greater than 230g per day) with a high average GI (greater than 70), reduce average daily available carbohydrate intake to 165g and GI to 45 for an average daily GL of 74g per 2000 calories, keeping type 2 diabetes risk to a minimum. An example meal plan could look something like this:
Read more:
- Salmerón et al. Dietary fiber, glycemic load, and risk of NIDDM in men. Diabetes Care, 1997.
- Dietary Glycemic Index and Load and the Risk of Type 2 Diabetes: A Systematic Review and Updated Meta-Analyses of Prospective Cohort Studies.
Alan Barclay, PhD is a consultant dietitian and chef (Cert III). He worked for Diabetes Australia (NSW) from 1998–2014 . He is author/co-author of more than 30 scientific publications, and author/co-author of The good Carbs Cookbook (Murdoch Books), Reversing Diabetes (Murdoch Books), The Low GI Diet: Managing Type 2 Diabetes (Hachette Australia) and The Ultimate Guide to Sugars and Sweeteners (The Experiment, New York).
Contact: You can follow him on Twitter or check out his website.
GOOD CARBS FOOD FACTS
CAULIFLOWER – THE ROCK STAR VEGETABLE
Was it the rock-star
chef Yotam Ottolenghi, or was it cauliflower rice that has created such
an aura around this humble brassica vegetable? I’m going with
Ottolenghi says dietitian Nicole Senior. Why? Because he’s all about
deliciousness and flavour and a food culture that has lasted for ages
and not a fad that has tarnished the name of all carbohydrates. And
there are so many more delicious ways to enjoy cauliflower than smashing
it to smithereens and imagining (very hard) that its potato.
Cauliflower is having its moment in the sun. It was
never really in the shade as it has been trundling along for years in
the form of cauliflower cheese (what’s not to love?), but since
Ottolenghi made vegetables cool again and showed us how to cook them in
delightful ways, cauli’s reputation has ramped up a notch or three. From
a new take on cauliflower cheese with mustard, cumin and curry, a
gorgeous salad with pomegranate and pistachios, a warming side dish with
coconut cream and chilli, or cauliflower “steaks” with Middle Eastern
Spices, Ottolenghi has indeed written the book on how to make this
sculptural looking vegetable into something marvellous and irresistible.
There
are many more beautiful recipes but my absolute go-to weeknight fast
and simple approach is to cut a whole cauliflower into four quarters
right down the stem, dress with crushed garlic and olive oil and roast
until tender (I stick it in the BBQ but a hot oven will do just as
well). It is simply divine and I can potter about doing the other bits
of the meal while it takes very good care of itself. Equally, you could
throw it into a roast vegetable medley and it will make beautiful
mouth-music with other veggies who like the lick of fire such as potato,
pumpkin (squash), eggplant (aubergine), capsicum (sweet pepper), carrot
and parsnip.
What makes all this cooking talk even
more appealing is learning just how good is it for your health.
Cauliflower, like other vegetables in the brassica family (also called
cruciferous vegetables because of their cross shaped flowers), contain
phytochemicals called flavonoids and glucosinolates that help support
your immune system and may even reduce cancer risk. It is also rich in
vitamin C for healthy gums, folate for a healthy heart, vitamin K for
controlling inflammation and fibre for good digestive health. And having
high water content and rich flavour while also being low in kilojoules,
it helps fill you up without filling you out.
And just when you thought we’d thought of everything
to do with cauliflower, some smarty pants in the Australian
horticultural industry thinks up the seemingly unthinkable – the
cauliflower latte. From the “what-will-they-think-of-next” basket, comes
an experimental milky coffee with 7g of cauliflower powder per cup that
was served up to delegates at a horticultural industry conference. The
baristas couldn’t keep up with demand! The word is it added a creamy
texture and took the bitter edge off the coffee. The idea behind it is
to use up otherwise wasted fresh cauliflower by transforming it into a
dry powder. The powder could also be used in a range of other foods such
as bread and improve vegetable intake as well as reduce food waste. I
thoroughly approve both these concepts but I can’t help thinking if we
all cooked cauli like Ottolenghi, we’d gobble up all the fresh
cauliflower there is going and there’d be no waste whatsoever.
THE GOOD CARBS KITCHEN
CRISPY CAULIFLOWER WITH BUCKWHEAT AND PINENUTS
0:10 Prep • 0: 30 Cook • 6 Servings • Easy
1 medium cauliflower
2 tablespoons olive oil
sea salt flakes
¾ cup raw buckwheat groats, rinsed
⅔ cup medium pitted black olives,
roughly chopped
2 tablespoons salted capers, rinsed and drained
3 tablespoons toasted pine nuts
2 tablespoons currants
Dressing
1 garlic clove, crushed
1 handful parsley, chopped
⅓ cup olive oil
2 tablespoons lemon juice
sea salt flakes and freshly ground pepper
Preheat
the oven to 190°C/375°F (fan 170°C/325°F). Line a baking tray with
baking paper. • Rinse the cauliflower and cut through the thick core
into quarters. Cut each quarter into thick slices and put into a bowl.
If you prefer, cut them into large florets. Pour over the oil, sprinkle
with a little salt and toss. Arrange the cauliflower on the tray and
roast for 20–25 minutes, or until crispy and slightly charred. Set aside
to cool. • While the cauliflower is roasting, bring a pot of water to
the boil, tip in the buckwheat and simmer for 8–10 minutes, or until al
dente. Drain, rinse and leave to cool to room temperature. • Whisk
together the dressing ingredients, adding salt and pepper to taste, to
make a chunky thick dressing. Watch the amount of salt you use, as both
the capers and olives will provide a briny tang. • Put the cauliflower,
buckwheat, olives, capers, pine nuts and currants in a bowl. Pour over
the dressing and lightly tumble together. Serve at room temperature.
NUTRITION
Per serve
1505kJ/ 360 calories; 6g protein; 27g fat (includes 3.5g saturated fat;
saturated : unsaturated fat ratio 0.15); 21g available carbs (includes
5.5g sugars and 15.5g starches); 5.5g fibre; 255mg sodium; 505mg
potassium; sodium : potassium ratio 0.5.
RECIPE
The Good Carbs Cookbook, Murdoch Books.
POTATO AND CAULIFLOWER MASALA DOSA
0:20 Prep • 0: 30 Cook • 6 Servings • Spice night
Masala
300g (10oz) potatoes, cut into 3 cm (1¼in) cubes
350g (12oz) cauliflower, cut into small florets
2 tablespoons curry leaves, plus extra to serve
olive oil spray
1 brown onion, sliced
2 long green chillies, sliced, plus extra to serve
30g (1oz) piece fresh ginger, finely grated
2 teaspoons yellow mustard seeds
1 teaspoon cumin seeds
½ teaspoon ground turmeric
coriander (cilantro) sprigs, to serve
150g (5½oz) reduced-fat plain yoghurt
Dosa
½ cup chickpea flour (besan)
½ cup wholemeal (wholewheat) flour
¼ cup rice flour
1 small handful coriander (cilantro), finely chopped
olive oil spray
To make the masala:
Put the potatoes in a saucepan of water and bring to the boil over high
heat. Reduce the heat and cook for 8 minutes. Add the cauliflower and
cook for a further 2–3 minutes or until the cauliflower is tender and
the potatoes are soft when tested with a knife. Drain the vegetables and
set aside. • Lightly spray the extra curry leaves with olive oil. Cook
in a large non-stick frying pan over medium heat for 1–2 minutes or
until crisp. Remove from the pan and set aside. • Spray the frying pan
with olive oil and place over
medium heat. Cook the onion, stirring, for 2–3 minutes or until
softened. Add the chillies, curry leaves, ginger, mustard seeds, cumin
seeds and turmeric. Cook, stirring, for 2–3 minutes or until aromatic.
Add the potatoes, cauliflower and ¼ cup water. Stir for 1 minute or
until the mixture is combined and the potatoes are slightly mashed.
Cover and keep warm while you cook the dosa.
To make the dosa:
Combine the flours with 1¼ cups water and whisk to make a
runny batter. Stir in the coriander. Spray a large frying pan with olive
oil and place over medium heat. Add one-quarter of the batter to the
pan, tilting and swirling to make a thin round. Cook for 2 minutes, then
turn over and cook for 1 minute or until golden. Transfer to a plate
and repeat with the remaining batter to make four dosa in total.
To serve:
Divide the potato mixture among the dosa, fold over and top with the
yoghurt, coriander sprigs, chilli and fried curry leaves. Sprinkle with
freshly ground black pepper and serve.
NUTRITION
Per serving
Energy 1225kJ/290 cals; protein 13g; fat 4g (includes 1g saturated fat;
saturated : unsaturated fat ratio 0.33); carbohydrate 48g (includes 9g
sugars and 39g starches); 8g fibre; 50mg sodium; 1070mg potassium;
sodium : potassium ratio 0.05.
RECIPE
Dr Alan Barclay, Reversing Diabetes, Murdoch Books.
POTATO SALAD WITH RED ONION
0:10 Prep • 0:15 Cook • 6 Servings • Easy
Photo: @megannevans.photography
INGREDIENTS
1kg (2lb 2oz) GiLicious™ potatoes,
¼ cup (60ml) extra virgin olive oil
Juice of 1 lemon
1 tablespoon white wine vinegar
½ medium red onion, cut into 2cm (¾in) pieces or finely diced if preferred
1 cup Italian parsley leaves, coarsely chopped
Sea salt and ground black pepper to taste
METHOD
Place
potatoes in a saucepan of salted boiling water and cook until just
tender. Drain potatoes and place in a bowl. • Whisk together the olive
oil, lemon juice and vinegar in a separate bowl. Add dressing to the
warm potatoes, together with the finely sliced or diced red onion and
chopped parsley, and toss well. • Season with salt and pepper to taste
and serve warm or cold.
NUTRITION
Per serving
Energy 725kJ/174 cals; Protein 4.9g; Fat 9.8g (includes 1.5g saturated
fat; saturated : unsaturated fat ratio 0.18); Carbohydrate 18.5g (3.5g
sugars, 15g starch), Fibre 4g; Sodium 221mg; Potassium 971mg (sodium :
potassium ratio 0.23)
RECIPE
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Nutritional analysis To analyse Australian foods, beverages, processed products and recipes, we use FoodWorks which contains the AusNut and Nuttab databases. If necessary, this is supplemented with data from www.calorieking.com.au or http://ndb.nal.usda.gov/ndb/search.
Disclaimer GI News endeavours to check the veracity of news stories cited in this free e-newsletter by referring to the primary source, but cannot be held responsible for inaccuracies in the articles so published. GI News provides links to other World Wide Web sites as a convenience to users, but cannot be held responsible for the content or availability of these sites. All recipes that are included within GI News have been analysed however they have not been tested for their glycemic index properties by an accredited laboratory according to the ISO standards.
© ®™ The University of Sydney, Australia
1 August 2019
GI News - August 2019
GI News is published online every month by the
University of Sydney, School of Life and Environmental Sciences and the
Charles Perkins Centre, and delivered to the mailboxes of our 97,000
subscribers. Our goal is to help people choose the high-quality carbs
that are digested at a rate that our bodies can comfortably accommodate
and to share the latest scientific findings on food and diet with a
particular focus on carbohydrates, dietary fibres, blood glucose and the
glycemic index.
Publisher: Professor Jennie Brand-Miller, AM, PhD, FAIFST, FNSA
Editor: Philippa Sandall
Scientific Editor/Managing Editor: Alan Barclay, PhD, APD, AN
Contact GI News: glycemic.index@gmail.com
Sydney University Glycemic Index Research Service
Manager: Fiona Atkinson, PhD, APD, AN
Contact: sugirs.manager@sydney.edu.au
Like us on
Follow us on
FOOD FOR THOUGHT
GOOD CARBS: THE ORIGINAL PLANT-BASED DIET
In
some quarters, carbs get an undeserved bad rap. But students of human
evolution know that dietary carbohydrates (fruits, berries and tubers)
played an instrumental role throughout our long 3-million-year journey
from a small upright walking ape (Lucy, Australopithicus afarensis) to
the tall, smooth-skinned creature with a very large brain who can
perform high level maths as well as prolonged strenuous marathons (Homo
sapiens sapiens). You could say we evolved eating the original
plant-based diet. The challenge today however, is to ensure we consume
the high-quality carbs similar to the ones our ancestors ate that are
digested at a rate that our bodies can accommodate, preventing burnout
of our insulin-producing machinery. In Food for Thought, we answer some
of the questions we are asked about the high-quality carbs we like to
call “good carbs”.
WHAT DO CARBS DO? Our brains, nervous system, red blood
cells, kidneys and muscles during exercise prefer carbs as their energy
source. Carbs also give our cells structure, form part of our genes and
play a part in the function of some proteins. Did you know that glucose
powers the growth of a healthy human fetus born with substantially more
body fat than any other primate.
WHAT ARE CARBS?
Carbohydrates are made up of carbon, hydrogen and oxygen, so you can
see where the name comes from. You may recall seeing it written up in
your high school science books as CHO. For example, the chemical formula
for glucose is C6H12O6 which stands for six carbon atoms and six water
molecules (H2O = one water molecule; six water molecules = H2O x 6).
All
plant foods contain carbs to a greater or lesser extent—fruits,
vegetables, legumes, grains and nuts—as do milk and yoghurt, but not
most cheeses (the whey is drained away so it is just protein and fat).
WHAT ARE GOOD CARBS?
These are the plant foods the natural world has provided for us: fruits
and berries, vegetables, beans, peas, lentils, seeds, nuts, and grains
and the traditional staple foods and dishes we make from them such as
noodles, pasta and grainy, seedy breads.
WHAT ABOUT MILK? Dairy
foods such as regular milk and yoghurt are good carbs too. And let’s
not forget mother’s milk which provides the perfect mix of carbs, fat,
protein, vitamins and minerals for our babies to grow and thrive for the
first six months of life. Mother Nature made it sweet so it is very
appealing to babies. The sweetness comes from a special sugar called
lactose only found in milk. Human milk has one of the highest
concentrations of lactose of any mammal coming in at around 7 grams of
lactose per 100 millilitres (3½ fluid ounces) which in household
measures is little over ⅓ cup. It contains almost 50% more than that of
cow’s milk. Why so much? One reason is probably to satisfy our
fast-growing, energy-hungry, glucose-demanding brain. Scans show that a
baby’s brain reaches more than half adult size in the first 90 days of
baby’s life. Mother’s milk also contains special carbs called
oligosaccharides (think of them as prebiotics), which friendly bacteria
in the large intestine chomp on to thrive.
WHAT’S SO GOOD ABOUT GOOD CARBS? They
are sustaining and sustainable foods that come with a swag of
micronutrients we need for good health including vitamins B, C and E;
minerals such as magnesium, potassium and calcium and antioxidants
including the carotenoids that play a protective role in eye health. Dan
Buettner’s Blue Zones studies provide compelling evidence that dietary
patterns that are rich in good carbs and dietary fibre reduce the risk
of weight gain, type 2 diabetes, coronary heart disease and certain
kinds of cancer, like colorectal cancer.
HOW MUCH CARBOHYDRATE DO WE NEED?
Our diet is not limited to One Size Fits All. You only have to look
around the world to see that there are very different dietary patterns
with very different fuel mixes associated with good health and long
life. Traditional Mediterranean and Japanese diets which are both linked
with a long and healthy life couldn’t be more different. The
Mediterranean diet is relatively high in fats and tends to be rather
moderate in carbs. The Japanese diet, like most Asian diets, is high in
carbs and low in fats. What they have in common and what seems to matter
most is that they are based on good, wholesome foods and ingredients.
Mostly plants.
WHAT ABOUT BLOOD GLUCOSE? When we
eat carb-rich foods, our bodies convert their sugars and/or starches
into glucose during digestion. However, our bodies do this at very
different rates and this is where using the glycemic index (GI) helps us
make better choices for long-term health and wellbeing. The GI is
particularly useful for people who need to manage their blood glucose
levels (BGLs). Think of it as a carbo speedo that gives us an idea how
quickly our bodies will digest particular carb foods and how fast and
high our BGL is then likely to rise.
Research around
the world over the past forty years shows that switching to eating
mainly low GI carbs throughout the day that will trickle glucose into
our bloodstream and lower our day-long blood glucose and insulin levels
helping us:
- Manage our appetite because we will feel fuller for longer
- Minimise our body fat
- Maximise our muscle mass
- Decrease our risk of type 2 diabetes and heart disease.
Read More:
WHAT’S NEW?
THE HUMBLE GLYCEMIC INDEX MARKS GLOBAL DIABETES RISK
ConscienHealth’s
Ted Kyle reports on a systematic review and meta-analysis of glycemic
index, glycemic load, and type 2 diabetes risk published in Nutrients by
an impressive global group of nutrition scientists. Their conclusions
are simple and powerful he says. Glycemic index and glycemic load are
important markers of food quality. In fact they do an excellent job of
predicting type 2 diabetes risk for individuals and for the population.
Almost 40 years ago, David Jenkins published the first paper to
propose that the glycemic index of foods might be an important measure
of nutrition quality. Back then, dietary guidance pointed to a low-fat
panacea. Research continued quietly on the glycemic index. The pendulum
swung from fear of fats to carbophobia. Sugar is the villain of the day
now. But maybe the time has come for the glycemic index to bring a bit
more objectivity.
Perhaps some of the energy that goes
into vilifying carbs, sugar, soda, and other dietary goblins would be
better spent directing people toward better carbs. “Don’t” has never
been an especially effective tool for behavior modification.
Senior
author on this new paper, Jennie Brand-Miller, explains the appeal of
the glycemic index: “I liked the fact that it turned traditional
nutritional science upside down. The old wisdoms were that sugars were
bad and starches were good, but the GI showed some starches, such as
potatoes, converted to glucose far quicker than some sugars. What
appealed most was that GI intuitively made sense. We all talk about
needing a sugar hit or having a sugar low, and this provided an
explanation. It provided a way in to explore how foods can affect not
just our physical health, but our moods as well.”
And
now we know that glycemic index is a good marker for how changes in the
food supply are driving an increased type 2 diabetes risk. Maybe now we
can move from the narrow focus on macronutrients to a broader view of
dietary quality. It looks like paying attention to this humble index
might help.
Read more:
WHAT’S HOT?
PLANT-BASED BURGERS
A
recent post in Refinery29 (“a modern woman's destination for how to
live a stylish, well-rounded life”) says “grilling up a good time
doesn't have to mean meat-based burgers for all. In fact, these days
there are a lot of meatless burger alternatives on the market. From
veggie and plant protein patties to quinoa and bean-based, non-meat
eaters have plenty of options when it comes to grilling out.” Their
reporter found that some people looked for trad veggie burgers, while
others want burgers to taste as much like real meat as possible.
Meat substitutes are certainly having a moment in the sun.
Writing for the New York Times, Timothy Egan says “fake meat will save
us.”
PR like that is an agency’s dream come true says
ConscienHealth’s Ted Kyle. So, it’s no wonder that Beyond Meat was
“going bananas” with a 550 percent surge in its stock price after a very
successful IPO. Its rival, Impossible Foods, can’t keep up with demand
for its Impossible Burger. That’s good news for farmers who can’t sell
their soybeans – a typical plant-based protein source. Suddenly, pea
protein is hot. Prices for this humble legume are rising, even though
soybean prices are depressed. The biggest meat processor in the U.S.,
Tyson Foods, is jumping in to build a billion-dollar brand with
half-pea, half-beef burgers. Kellogg is supposedly sitting on a goldmine
with its Morningstar Farms brand for fake meat.
Kyle
asks if PR spin is tapping into foodie moralism to make this highly
processed food seem like a healthy choice? Yes, indeed, he says. We need
to move toward a more sustainable diet that won’t destroy the planet he
says. Fake burgers, though? It’s unlikely they’ll give us a healthier
diet. Maybe it’s time to remind ourselves of Michael Pollan’s top tip:
“Eat food, not too much, mostly plants.” By food Pollan means fruit,
vegetables, fruits, legumes, whole grains, nuts and seeds, seafood,
poultry and meat and to avoid what he calls “edible food-like
substances.”
Read more:
PRODUCT REVIEW
BURGERS
Since
everyone seems to be talking (and eating) burgers, we thought it would
be interesting to compare a regular lean beef patty that just contains
lean beef, with a meatless patty (we chose the top-seller Beyond Meat
Beyond Burger™) and a homemade chickpea patty (the recipe is from The Low GI Vegetarian Cookbook). The nutrition information here is for the patty alone.
LEAN BEEF PATTY
Ingredients: Lean minced beef.
BEYOND MEAT BEYOND BURGER
Ingredients:
Water, Pea Protein Isolate*, Expeller-Pressed Canola Oil, Refined
Coconut Oil, Rice Protein, Natural Flavors, Cocoa Butter, Mung Bean
Protein, Methylcellulose, Potato Starch, Apple Extract, Salt, Potassium
Chloride, Vinegar, Lemon Juice Concentrate, Sunflower Lecithin,
Pomegranate Fruit Powder, Beet Juice Extract (for color).
(*Peas
are legumes. People with severe allergies to legumes like peanuts
should be cautious when introducing pea protein into their diet because
of the possibility of a pea allergy. Our products do not contain peanuts
or tree nuts.)
CHICKPEA PATTY
Ingredients: 400g
(14oz) can chickpeas, rinsed and drained, 1½ tablespoons olive oil, 1
onion, finely chopped, 1 garlic clove, crushed, 1 tablespoon mild Indian
curry paste, 1 zucchini, grated, 110g (4oz/1½ cups) firmly packed fresh
wholegrain breadcrumbs, 1 tablespoon freshly chopped coriander, 1 egg,
lightly beaten, Wholemeal plain flour, to dust. Serves 4.
Read more:
PERSPECTIVES WITH DR ALAN BARCLAY
LOW CARB?
Low carb diets are still very popular in many
parts of the world. The problem is, many people do not seem to really
understand what “carbs” actually are. Consumer research in Europe, for
example, has found that only 51% of consumers can correctly identify a
carbohydrate. This is not really surprising, because carbohydrates are
complicated and not currently well described on food labels.
CARBS IN FOODS Carbohydrates include varieties that are digestible by humans (known scientifically as available carbohydrates):
- Oligosaccharides (e.g., maltodextrins)
- Starches (e.g., amylose and amylopectin)
- Sugars (e.g., fructose, galactose, glucose, lactose, maltose and sucrose)
- Dietary fibres (e.g., cellulose, gums, hemicellulose, mucilages and pectins)
- Fruits
- Grains (e.g., barley, oats, rice, rye, wheat, etc.)
- Legumes (e.g., peas, beans, lentils, chickpeas, etc.)
- Milk
- Nuts
- Seeds
- Vegetables
- Yoghurt
- Flours (e.g., plain wheat flour)
- Sugars (e.g., table sugar, or sucrose)
- Dietary fibres (e.g., pectin)
North Americans are provided with more information – Nutrition Facts panels must include:
- Total carbohydrate
- Dietary fiber
- Total sugars
- Added sugars
WHAT DOES “LOW CARB” MEAN? Many people that are following low carb diets today are in reality following low starch diets that primarily exclude or limit grains (e.g., breakfast cereals, breads, pastas, rice, etc...) and starchy vegetables (e.g., corn, potatoes, peas, etc...). Most aren’t specifically aiming to exclude dietary fibre, although a reduced fibre intake is often an unwanted side-effect.
Even the definition of a low carb diet is hotly debated. One of the more popular systems classifies diets according to the amount of total available carbohydrate they provide:
- Very low-carbohydrate diet. 20–50 grams per day or less than 10% of a 2000 Calorie (8,400 kJ diet)
- Low carbohydrate diet. Less than 130 grams per day or less than 26% of energy from a 2000 Calorie (8,400 kJ diet)
- Moderate carbohydrate diet. 130–230 grams per day, or 26–45% of energy from a 2000 Calorie (8,400 kJ diet)
- High carbohydrate diet. More than 230 grams per day or more than 45% of energy from a 2000 Calorie (8,400 kJ diet)
HOW MUCH CARBOHYDRATE ARE WE EATING? Many people in the developed world could be forgiven for thinking that our diets are high in carbohydrate, and should reduce our intakes. However, we know from the latest Australian Health Survey that on average, Australian adults consumed an average of 222 grams of carbohydrate per day in 2011–12, or 44% of energy from carbohydrates, putting them in the moderate carbohydrate diet camp.
ENJOY GOOD CARBS Most people in the developed world don’t need to consume a low carbohydrate diet. Enjoying a traditional dietary pattern with a long history of health, well-being and longevity, like the traditional Mediterranean diet or Japanese diet, is a better strategy – and both diets contain plenty of fruit and vegetables, something most people don’t eat enough of.
Read more:
- Literature review on consumer knowledge, attitudes and behaviours relating to sugars and food labelling
- Australian Health Survey: Nutrition First Results - Foods and Nutrients, 2011-12
Alan Barclay, PhD is a consultant dietitian and chef (Cert III). He worked for Diabetes Australia (NSW) from 1998–2014 . He is author/co-author of more than 30 scientific publications, and author/co-author of The good Carbs Cookbook (Murdoch Books), Reversing Diabetes (Murdoch Books), The Low GI Diet: Managing Type 2 Diabetes (Hachette Australia) and The Ultimate Guide to Sugars and Sweeteners (The Experiment, New York).
Contact: You can follow him on Twitter or check out his website.
GOOD CARBS FOOD FACTS
SWEET CORN
It’s hard to beat the juicy burst of sweet corn
kernels straight from the cob. Peel back the husk of a fresh ear of corn
(stripping away the silk) and we are munching through the neat rows of
yellow or white kernels of a very big grass seed head that was
cultivated in the Americas for thousands of years before Christopher
Columbus arrived on the scene.
Although “officially” a grain, the particular variety we tuck
into is very much eaten immature as a vegetable. Boil, steam, microwave,
bake or barbecue and serve piping hot with just a dot of butter and
sprinkle of salt. Or add the kernels to soups, stews and stir fries;
fritters and frittatas; chowders and crepes; salsas and salads; muffins,
breads and corn cakes, and toss whole baby corn into stir-fries.
Buy
cobs with fresh green unblemished husks that fit snugly with moist
slightly brown silky tassels intact. (If the tassels are black or dry,
the corn is old: if dry and pale the corn is immature) if you can get a
peek at the kernels, they should be tightly packed, plump, shiny and
smaller at the tip than they are in the middle (this indicates a young
cob). When sweet corn is really fresh, the kernels will release a milky
liquid when cut. As the natural sugars in the kernels start converting
to starch once the husk is removed, resist buying pre-packed shucked
ears. Snap-frozen cobs and kernels make a handy year-round substitute.
Wholegrain products made from corn include:
- Polenta, a coarsely ground dried corn that is actually a type of grits. (Avoid instant polenta, it may be convenient and foolproof but it’s not the same at all.)
- Corn grits, which are chopped up dried kernels that you can use in soups or stews or serve as a side dish.
- Hominy grits are corn grits that have been treated with an alkaline solution (nixtamalized).
Source:
THE GOOD CARBS KITCHEN
It’s all about corn this month with Barbecued Corn with Avocado Cream from Dr Alan Barclay’s book, Reversing Diabetes; Chicken and Corn Soup with Toasted Tortilla and Avocado from The Good Carbs Cookbook; and for the kids, Diane Temple’s Chicken and Corn Nuggets from the Money Saving Meals series we ran in 2010.
BARBECUED CORN WITH AVOCADO CREAM
The avocado cream can also be used as a creamy topping for jacket potatoes
or as a spread for toast or sandwiches says Alan Barclay. It’s full of
healthy unsaturated fats, dietary fibre and potassium.
Serves 2 • Preparation 5 minutes + 15 minutes soaking • Cooking 20 minutes
2 corn cobs, husks attached
1 long red chilli, finely chopped
lime cheeks, to serve
For the avocado cream
1 small avocado
1 tablespoon lime juice
¼ tsp cayenne pepper
tablespoon coriander (cilantro) leaves, finely chopped
Peel
back the husks from the corn cobs, discard the silk and remove several
of the inside husks, leaving a few outer husks to protect and steam the
corn while it is cooking. Soak the corn cobs and two pieces of string in
a large bowl of water for 15 minutes. • Meanwhile, to make the avocado
cream, use a stick blender or small food processor to blend the avocado,
lime juice and cayenne pepper until it reaches a smooth, spreadable
consistency. Stir in the coriander and set aside until needed. • Preheat
a barbecue or chargrill pan to medium–high. Drain the corn cobs, reseal
the husks and secure with the wet string. Cook the corn, turning
occasionally, for 15–20 minutes or until tender. • Peel back the husks
and spread the corn with the avocado cream. Sprinkle with the chilli and
serve with lime cheeks.
Per serving
Energy
1790kJ/426 calories; Protein 9g; Fat 29g (includes 6g saturated fat;
saturated : unsaturated fat ratio 0.26); Carbohydrate 27g (includes 4g
sugars and 23g starches); Fibre 9g; Sodium 9mg; Potassium 1475mg; sodium
: potassium ratio 0.01
CHICKEN AND CORN SOUP WITH TOASTED TORTILLA AND AVOCADO
Much of the depth of flavour in this soup comes from the first step of
gently cooking the veggies in oil says Kate McGhie. Once there’s a
slight sizzle, put the lid on the pan to keep the aromatic moisture in
while the veggies soften. Her top tip? Cook the chicken the day before
and use the stock for the soup. • Preparation time: 25 minutes • Cooking
time: 25 minutes • Serves: 8
2 tablespoons olive oil
1 medium onion, finely chopped
2 garlic cloves, crushed
1 medium zucchini, finely diced
1 medium carrot, finely diced
2½ litres chicken broth
400g (14oz) can chick peas, rinsed
Salt flakes
2 medium (about 320g) boneless, skinless chicken breasts, poached
1 small red chilli, finely chopped
2 handfuls coriander (cilantro) leaves, coarsely chopped
3 large tortillas
1 medium avocado, sliced
1 small lime, cut into thin wedges
Put the oil in a large pot and when hot add the onion, garlic, zucchini and
carrot. Cook gently until the vegetables soften and then add the
chicken stock, chick peas and salt to taste. Cover and simmer for 15
minutes. • Shred the chicken and stir through the hot soup with the
chilli and half of the coriander. • Lightly toast the torillas and cut
into fine strips. • Ladle the soup into bowls, garnish with a few
avocado slices, some tortilla strips, remaining coriander and serve with
lime wedges for squeezing over the soup.
Per serving
Energy 1540kJ/370 calories; Protein 26g; Fat 19g (includes 4g saturated fat;
saturated : unsaturated fat ratio 0.3); Carbohydrate 21g (includes 4g
sugars and 17g starches); Fibre 7g; Sodium 1030mg; Potassium 695mg;
sodium : potassium ratio 1.48
CHICKEN AND CORN NUGGETS
The next time the clamour for takeaway starts, try these lightly pan-fried
nuggets for a quick and easy, budget friendly meal instead. You can also
bake them, but they’ll take a little longer to cook. The nuggets also
double as tasty finger food when entertaining and leftovers (if there
are any) are ideal for lunch boxes says Diane Temple. Makes about 30
500g (1lb 2oz) chicken mince
1 tablespoon soy sauce
2 cloves garlic, crushed
125g (4oz) can corn kernels, drained
1 cup fresh breadcrumbs made from grainy bread
2 tablespoons chopped chives
½ cup panko crumbs
2 tablespoons canola oil
To serve
Celery and carrot sticks
Tiny tomatoes
Blanched snowpeas (mangetout) or sugar snap peas
Crispy green beans
Tomato, barbecue or sweet chilli sauce
Mix
the chicken mince, soy sauce, garlic, corn kernels, fresh breadcrumbs
and chives together. With damp hands, roll 1 tablespoon of the mixture
into a ball, then flatten it slightly. Repeat with the rest of the
mixture. Roll each nugget in dry breadcrumbs and chill in the fridge for
10–20 minutes. • Heat the oil in a large non-stick frying pan and cook
the nuggets in batches (about 2 minutes each side) until golden brown
and cooked through. Place them on a tray lined with paper towel. Repeat
with remaining nuggets.
Per nugget
Energy: 236kJ/ 56 calories; Protein 4g; Fat 4g (includes 0.5g saturated fat, saturated :
unsaturated fat ratio 0.1); Carbohydrate 3g; Fibre 9g
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Nutritional analysis To analyse Australian foods, beverages, processed products and recipes, we use FoodWorks which contains the AusNut and Nuttab databases. If necessary, this is supplemented with data from www.calorieking.com.au or http://ndb.nal.usda.gov/ndb/search.
Disclaimer GI News endeavours to check the veracity of news stories cited in this free e-newsletter by referring to the primary source, but cannot be held responsible for inaccuracies in the articles so published. GI News provides links to other World Wide Web sites as a convenience to users, but cannot be held responsible for the content or availability of these sites. All recipes that are included within GI News have been analysed however they have not been tested for their glycemic index properties by an accredited laboratory according to the ISO standards.
© ®™ The University of Sydney, Australia
1 July 2019
GI News - July 2019
GI News is published online every month by the
University of Sydney, School of Life and Environmental Sciences and the
Charles Perkins Centre, and delivered to the mailboxes of our 97,000
subscribers. Our goal is to help people choose the high-quality carbs
that are digested at a rate that our bodies can comfortably accommodate
and to share the latest scientific findings on food and diet with a
particular focus on carbohydrates, dietary fibres, blood glucose and the
glycemic index.
Publisher: Professor Jennie Brand-Miller, AM, PhD, FAIFST, FNSA
Editor: Philippa Sandall
Scientific Editor/Managing Editor: Alan Barclay, PhD, APD, AN
Contact GI News: glycemic.index@gmail.com
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FOOD FOR THOUGHT
PROTEIN QandA: OUR EXPERTS ANSWER YOUR QUESTIONS
Prof Jennie Brand-Miller and Dr Alan Barclay answer the most common questions we are asked about protein.
WHAT IS PROTEIN?
People talk about “protein”, but in fact there are many proteins. They
are chemical compounds made up of chains of smaller building blocks
called amino acids. There are about 20 different amino acids that come
together in different combinations to make up the millions of proteins
found in nature. A protein can consist of between 50 and tens of
thousands of amino acids.
WHAT ARE AMINO ACIDS? An
amino acid consists of a central carbon atom, linked to an amino group
(an atom of nitrogen + hydrogen atoms), a carboxylic acid group (an atom
of carbon + oxygen atoms), a hydrogen atom, and a distinctive R group,
which is referred to as the side chain. The unique composition of the R
group is what makes all of the amino acids different.
In addition to being the building blocks of proteins, the cells
of our bodies use amino acids to form nerve transmitters and hormones
(e.g. adrenalin and insulin). They can also be used as an energy source,
particularly when carbohydrate and fat are restricted. Amino acids are
generally divided into two broad classes – those that our bodies can
make (non-essential amino acids), and those we have to get through our
diet (essential amino acids).
WHY DO WE NEED PROTEIN? We need to consume protein for the
growth, development and maintenance of our body tissues because it’s an
essential part of the structure and function of every cell in our body.
Consuming protein brings a couple of bonus side-effects. First up,
protein-rich foods are more appetite satisfying compared with carb- and
fat-rich foods and can reduce those pesky hunger pangs between meals. In
addition, protein increases our metabolic rate for one to three hours
after eating. This means we burn more energy by the minute compared with
the increase that occurs after eating carbs or fats.
WHERE DO WE GET IT?
Protein is widely available in our food supply. And while people talk
about “protein foods”, no food is all protein and most of us eat a
variety of foods containing many different proteins. We are often asked
what are the best sources. The answer is easy: whole foods which provide
us with other things our bodies need such as vitamins, minerals and
dietary fibre. As Dr David Katz says: “Dietary protein does not require
animal foods, and does not require any specific food combinations.
Wholesome foods in any balanced, sensible assembly – even a strictly
vegan assembly – will readily provide it.”
Animal sources:
• Meat, poultry, and seafood
• Eggs
• Milk, cheese and yoghurt.
Plant sources:
• Beans, chickpeas or lentils (legumes/pulses)
• Nuts and seeds
• Grains, especially whole grains
• Starchy veggies
HOW MUCH DO WE NEED?
Because our bodies don’t stockpile large amounts of protein from one
day to use up the next, we need to top up the protein tank every day. We
don’t need a lot – in fact, the average adult needs less than 1 gram of
protein per kilogram of healthy body weight a day. So, it isn’t hard to
do and most of us living in developed nations get more than enough.
Children, teenagers, pregnant women and women who are breastfeeding need
more as do people recovering from an injury or a major illness.
Athletes, weekend warriors and people who work out vigorously also need
more for building and repairing muscles. People with diabetes do have an
increase in protein turnover because of their high blood glucose levels
and this increases the body’s protein needs slightly. However, because
most people are already consuming much more protein than necessary,
eating more is not usually recommended. Remember, excess calories from
protein are still excess calories and they will do what all excess
calories do, turn into stored body fat.
WHAT ABOUT PROTEIN AND BLOOD GLUCOSE? Up
to half the protein we eat will eventually be converted to glucose via a
process called gluconeogenesis (which literally means the creation of
new glucose). However, our glucose concentrations do not rise and fall
in any marked way after we eat a protein-rich meal because our bodies
balance the rate of glucose production with the rate of glucose burning.
While protein does not directly affect blood glucose levels, it does
stimulate secretion of significant amounts of insulin depending on the
protein source. Research to-date suggests whey protein (often used in
protein-supplemented foods) is the most potent insulin stimulator,
followed by fish, beef, eggs and chicken.
WHAT ARE PROTEIN SUPPLEMENTS? These
are the high protein balls, bars, shakes and powders you’ll find in
gyms, health food stores and supermarkets. Consuming them is not the
same as eating protein-rich wholefoods such as a piece of meat, a
handful of nuts or a tub of yoghurt, as they provide few nutrients apart
from protein. They are typically highly processed made with either soy
or whey protein such as:
- Soy protein isolate, which is extracted, refined protein from the soy bean.
- Whey protein concentrate, which is extracted protein from whey (the leftover liquid from milk formed during the production of cheese). It retains many of the bioactive compounds of the whey, along with small amounts of fat and lactose.
- Whey protein isolate, which is further refined so that it is almost entirely protein.
- Whey protein hydrolysate which is where the proteins have been partially broken down for quicker digestion and absorption.
WHO NEEDS PROTEIN SUPPLEMENTS? No one really needs supplemental protein says the American College of Sports Medicine. Athletes do require more protein than the rest of us, but can generally get it from a good mixed diet. However, consuming protein right after a vigorous workout can help you recover and gain muscle mass. “A good choice for the post workout would be a whey-based protein shake or a home-made protein shake made with milk, yoghurt and fruit as it will be absorbed more quickly than solid food and this is key for timing,” says dietitian and nutritionist Dr Joanna McMillan.
Read More:
WHAT’S NEW?
MODERNIZING THE DEFINITION OF PROTEIN QUALITY
Dr
David Katz and colleagues call for the definition of protein quality to
be modernized in their recent paper in Advances in Nutrition, because
the current definition is misleading and antiquated they say.
Historically, protein quality has been defined in biochemical and
physiological terms reflecting the concentration of the 9 essential
amino acids and their digestibility from specific food sources. The
resulting measure, the Protein Digestibility Corrected Amino Acid Score
(PDCAAS), is what the Food and Drug Administration (FDA) in the United
States uses to measure protein quality in foods.
Katz and his colleagues explain why it is obsolete. “The popular
concept that protein is “good,” and that the more the better, coupled
with a protein quality definition that favors meat, fosters the
impression that eating more meat, as well as eggs and dairy, is
desirable and preferable. This message, however, is directly opposed to
current Dietary Guidelines for Americans, which encourage consumption of
more plant foods and less meat, and at odds with the literature on the
environmental impacts of foods, from carbon emissions to water
utilization, which decisively favor plant protein sources. Thus, the
message conveyed by the current definitions of protein quality is at
odds with imperatives of public and planetary health alike.”
In
their paper, Katz and colleagues propose a modernized definition, which
incorporates the quality of health and environmental outcomes
associated with specific food sources of protein.
They
also demonstrate how such an approach can be adapted into a metric, and
applied to the food supply. Their metric still considers the
distribution of essential amino acids, and their digestibility – but
also considers, and weights appropriately, the net effects of the food
on our overall health, and its environmental footprint. By such a
measure, beans and lentils shoot up to the top of the rankings, and
beef, for example, falls down because while it is indeed a concentrated
protein source, it’s a food we should be eating less, not more. They
conclude: “The adoption of such a shift in protein quality assessment
would allow for clearer, more consistent messaging to the public and
better alignment of nutrition policy with nutrition science.”
Read more: