1 February 2006

Feedback—Your FAQs Answered

My husband and I are following the 12-week Action Plan in The Low GI Diet. However, I am currently breastfeeding and I wonder whether you need to eat a little more than usual to allow for lactation or pregnancy?
Increased energy intake is recommended during pregnancy and lactation. The greatest requirement is for lactation—add 2000 kJ (500kcal) to daily requirements. In early pregnancy there is no greater need but by the 3rd trimester an extra 2000 kJ (500kcal) are recommended daily. This is based on a normal/healthy pre-existing body weight. If you are already overweight then you wouldn't need to increase by so much.
Estimations of energy requirement should always be taken as a guide only. Differences between people can be enormous. Often it is more realistic to use appetite as a guide to whether you are eating enough.


The increased calories can come from any source (carbohydrate, protein or fat) but it is safest to increase calories from carbohydrate or protein if you are unsure about amounts, because these nutrients have the greatest effect on satiety.

I haven't been able to find a reference as to what GI number a person should shoot for when trying to diet. Is there a formula, such as "take goal weight, multiply by age, divide by activity level?
The simple answer is no, there’s no formula. You don’t need to add up the GI each day. In fact there’s no counting at all as there is with calories/kilojoules. The basic technique for eating the low GI way is simply ‘This For That’: swapping the high GI carbs in your diet with low GI foods. This could mean eating muesli at breakfast instead of wheat flakes, low GI bread instead of normal white or wholemeal bread, or a sparkling apple juice in place of a soft drink. So, what you need ‘to shoot for’ is identifying the high GI carbs in your current diet and swapping them for some quality low GI carbs. Dietitian Kaye Foster-Powell says in Low GI Eating Made Easy: ‘We have found that many people who substitute low for high GI foods in their everyday meals and snacks reduce the overall GI of their diet, gain better blood glucose control and lose weight.

Kaye Foster-Powell

If you are looking for some guidelines, here’s how she answers the ‘what do I eat’ question. Every day you need to:

  • Eat at least three meals—don’t skip meals. Eat snacks too if you are hungry.
  • Eat fruit at least twice—fresh, cooked, dried, juices.
  • Eat vegetables at least twice—cooked, raw, salads, soups, juices and snacks.
  • Eat a cereal at least once—such as bread, breakfast cereal, pasta, noodles, rice and other grains in a wholegrain or low GI form
  • Accumulate 60 minutes of physical activity (including incidental activity and planned exercise).
  • Every week you need to:
  • Eat beans, peas and/or lentils—at least twice. This includes baked beans, chickpeas, red kidney beans, butter beans, split peas and foods made from them such as hommous and dhal.
  • Eat fish and seafood at least once, preferably twice, each week—fresh, smoked, frozen or canned.
  • Eat nuts regularly—just a tiny handful.
I’m confused. What’s the difference between GI and GL? Should I use GI or GL and does it really matter?
Your blood glucose rises and falls when you eat a food or meal containing carbohydrate. How high it rises and how long it remains high depends on the quality of the carbohydrate (its glycemic index value or GI) as well as the quantity of carbohydrate in your meal. Researchers at Harvard University came up with a term that combines these two factors—glycemic load (GL). Some people think that GL should be used instead of GI when comparing foods because it reflects the glycemic impact of both the quantity and quality of carbohydrate in a food. But more often than not, it’s low GI not low GL that predicts good health outcomes. So which one should you use?

We are often asked this question. Our advice is to stick with the GI rather than GL—the reason being that following the low glycemic load (GL) route can lead you straight to a low carb diet: ie fatty meats and butter, for example have a low GL. .
But if you eat plenty of low GI foods, you’ll find that you are automatically reducing the GL of your diet and at the same time you’ll feel fuller for longer with these satisfying carbohydrate-containing foods, as well as improve many health parameters.

We also emphasise that there’s no need to get overly technical about this. Think of the GI as a tool allowing you to choose one food over another in the same food group—the best bread to choose, the best cereal to choose etc.—and don’t get bogged down with figures. A low GI diet is about eating a wide variety of healthy foods that fuel our bodies best—on the whole these are the less processed and wholesome foods that will provide carbs in a slow release form.
The take-home message:
  • Slow carbs, not low carbs
  • Use GI to identify the best carbohydrate choices.
  • Take care with portion size with carb-rich foods to limit the overall GL of your diet.
How do you figure out the GL numbers?
Glycemic load is calculated simply by multiplying the GI of a food by the amount of carbohydrate in the portion (in grams) you are eating and dividing by 100. Here’s how
Glycemic load = (GI x carbohydrate per serving) ÷ 100
Let’s say you wanted to have an apple for a snack. Apples have a GI of 40 and 1 medium apple contains 15 grams of carbohydrate.
So, the glycemic load of your apple snack is (40 x 15) ÷ 100 = 6.
If you were very hungry and tucked into 2 apples you be eating 30 grams of carbs and the GL of your snack would be 12. The GI doesn’t change, but you are eating more carbs because you are eating 2 apples.


Does Low Carb automatically mean low GI?
Not at all. Here’s why. Low carb is just about quantity; it simply means that a food or meal does not contain much carbohydrate at all. It says nothing about the quality of the carbs in the food or meal on your plate. You could be eating a low carb meal but the carbs have a medium or high GI. Low GI on the other hand is all about quality.

Photo: Ian Hofstetter, www.ianhofstetter.com.au The Low GI Diet Cookbook

Whether you are a moderate or high carb eater, low GI carbs (wholegrain breads, legumes /pulses, many fruits and vegetables) will have significant health benefits—promoting weight control, reducing your blood and insulin levels throughout the day, and increasing your sense of feeling full and satisfied after eating. We suggest that you make the most of quality carbs and reap the add-on health benefits such as:
  • Vitamin E from wholegrain cereals
  • Vitamin C, beta-carotene and potassium from fruits and vegetables
  • Vitamin B6 from bananas and wholegrain cereals
  • Pantothenic acid, zinc, iron and magnesium from wholegrains and legumes
  • Anti-oxidants and phytochemicals from all plant foods
  • And fibre which comes from all of the above and doesn’t come from any animal food


Anonymous said...

The question I asked last month regarding the effect GI diet might have on prostate cancer patients has'nt been answered yet. I really do need to know if the PSA count can be increased by any of the foods recommended in the diet, especially porridge oats. Help!

GI Group said...

Hi - sorry about the delayed response. An article has been publshed on this:

Glycemic index, glycemic load and risk of prostate cancer.
Int J Cancer. 2004; 112(3):446-50.

Dietary carbohydrates have different glycemic and insulinemic potentials depending on type (glycemic index, GI) and amount (glycemic load, GL) of carbohydrate consumed or both. Insulin in turn has been implicated as a risk factor for several cancers, including that of the prostate. We assessed the relationship of GI and GL with prostate cancer risk in a multicenter case-control study. Cases and controls were recruited between 1991 and 2002 in the network of major teaching and general hospitals in 4 Italian areas. Cases were 1,204 men (age range 46-74 years) admitted for incident, histologically confirmed prostate cancer. Controls were 1,352 men (age range 46-74 years) admitted for acute, nonmalignant conditions unrelated to long-term modifications of diet. ORs of prostate cancer and the corresponding 95% CIs were derived using unconditional multiple logistic regression, including terms for age, study center, education, family history of prostate cancer, smoking, body mass index, physical activity, alcohol consumption, intake of energy, fiber and lycopenes. Compared to the lowest quintile of GI, the ORs were 1.23, 1.24, 1.47 and 1.57 for subsequent levels of GI. The corresponding values for GL were 0.91, 1.00, 1.20 and 1.41. No heterogeneity was found among strata of selected covariates. We found direct relations between dietary GI and GL and prostate cancer risk. Correcting for potential confounding factors did not substantially modify these associations.

GI Group

Anonymous said...

Last January, an endocrinologist put me on a low GI diet for obesity. I knew I had hyperinsulinism but didn't know you could do anything about it. Over about eight months, I lost 28 kilos. I was extatic that at last there was a diet I could stick to. At last, I felt,It's official : it's "not my fault", it's not about will-power. Well, since November, I've no longer been able to stick to the diet, I've put on maybe eight kilos and I'm desperately disappointed. At the beginning, it was so easy to stick to - no temptation was strong enough. Now, it's almost gone back to the way it was before. My endocrinologist is professor Martin Buysschaert from Brussels, a European authority, I can't get another appointment until April. Plese help me to get back on track, as I'm still morbibly obese and worry constantly about it.

Anonymous said...

why do you not give the GI of tofu?

GI Group said...

>>>why do you not give the GI of tofu?

Tofu contains far too little carbohydrate per serving to have a GI.

Anonymous said...

Is it true that one low GI food in a meal lowers the GI of the whole meal? Also that fat lowers the GI of the Meal (so that traditional roast potatoes are low GI?).

Currently I use a handful of sunflower seeds with a meal to lower the GI if I cannot change it any other way (eg I'm being cooked a meal by my mother!). Is this OK?

hermin said...

i applaud your 'creative' idea by adding sunflower seeds to your meal, NOT because they lower the overall GI of your meal, BUT as they contain plenty of essential fatty acids (omega 6) + vitamin E, that should be great. if you substitute the seeds with animal fat, though, i reckon it'll be a problem.

hermin said...

just wondering whether resistant starch DOES increase fat burning (a.k.a oxidation)? if so, how does it work? thanks.