1 May 2006

GI News Briefs

Slimmer But Not Healthier
Low carb diets promise (and deliver) rapid weight loss without hunger in the first and most restrictive phase of the diet. That’s why they are popular – everyone likes quick results. Within a few days the scales will show a real difference. But is there a health cost? To date, no low-carbohydrate intervention trials have been of sufficient duration to investigate long-term effects of low-carb diets. But a recent issue of the Lancet reports life-threatening complication that occurred in the short-term. A 40-year old obese woman who strictly followed the low-carb, high-protein Atkins diet for a month ate meat, cheese and salads, took the prescribed Atkins supplements and monitored her urine – all by ‘The Book’. She lost 9 kg in the first month at the end of which she was admitted to New York’s Lenox Hill Hospital intensive care unit with severe ketoacidosis – a condition that occurs when high levels of acids called ketones build up in the blood.

‘Ketones are produced in the liver whenever there is decreased insulin during starvation. A low-carbohydrate diet such as Atkins can lead to ketone production; in fact, the Atkins diet book recommends regular monitoring for ketonuria to confirm adherence to the diet … Our patient had an underlying ketosis caused by the Atkins diet and developed severe ketoacidosis, possibly when her oral intake was compromised from mild pancreatitis or gastroenteritis. This problem may become more recognised because this diet is becoming increasingly popular worldwide,’ say Tsuh-Yin Chen and co- authors.
Lancet: 2006 (vol 367, pp958)

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Commenting in the Lancet, Lyn Steffen and Jennifer Nettleton from the University of Minnesota School of Public Health say: ‘Teaching at-risk individuals how to manage their weight in ways that are healthy and can be maintained for a lifetime is of utmost importance. Traditional and healthy weight-control practices include increasing physical activity and modifying dietary patterns, such as increasing intakes of wholegrain products and fruit and vegetables. Many longitudinal epidemiological studies have shown significantly lower risk of cardiovascular disease, stroke, cancer, and other conditions associated with consumption of fruits, vegetables, and whole-grains; some of these foods are noticeably absent from the menu of low-carbohydrate diets.’ They conclude with the point that: ‘As researchers and clinicians, our most important criterion should be indisputable safety, and low-carbohydrate diets currently fall short of this benchmark.’
– The Lancet: 2006 (vol 367, pp880–1

GI Group: What You Should Know About Low Carb Diets and Ketosis
‘At all times, our bodies need to maintain a minimum threshold level of glucose in the blood to serve the brain and central nervous system,’ write Prof Jennie Brand-Miller, Kaye Foster-Powell and Joanna McMillan-Price in The Low GI Diet. 'If, for some reason, glucose levels fall below this threshold (a very rare state called hypoglycemia), the consequences are severe including trembling, dizziness, nausea, incoherent rambling speech, and lack of coordination. When necessary, the brain will make use of ketones, a byproduct of the breakdown of fat. In people losing weight on a low carb diet, the level of ketones in the blood rises markedly, a state called ketosis, which is taken as a sign of "success". The brain, however, is definitely not at its best using ketones, and mental judgement is impaired. Ketosis is a serious concern in pregnant women. The foetus can be harmed and brain development impaired by high levels of ketones crossing from the mother’s blood via the placenta. Because being overweight is often a cause of infertility, women who are losing weight may fall pregnant unexpectedly. Thus one of the very good reasons we advocate a healthy low GI diet in this context is that there are absolutely no safety concerns for mother or baby. Indeed, there is some evidence that a low GI diet will help mothers control excessive weight gain during pregnancy.' We’ve summarised all the benefits of The Low GI Diet over a low carb diet.

The Low GI Diet
You feel good, you can think straight
You lose fat, not water and muscle
You have energy for exercise
Low in saturated and trans fats
No concerns about safety in children
No concerns about safety in pregnancy
Benefits for mental function
Value-added benefits for long-term health

Low Carb Diets
You may feel headachy and light-headed
You lose fat, water and muscle
Insulin sensitivity is enhanced
Glucose tolerance worsens
You feel lethargic, exercise is tough
Unavoidably high in the bad fats
Immense concerns about safety in children
Immense concerns about safety in pregnancy
Decline in mental performance
Serious doubts about long-term safety

(The Low GI Diet is published by Hachette Livre in Australia and New Zealand, Hodder Mobius in the UK and Marlowe & Company in the US)

Going with the Grain
As we have said before, there are countless reasons to include more whole cereal grains in your diet, but it’s hard to go past the fact that you are getting all the benefits of their vitamins, minerals, protein, dietary fibre and protective anti-oxidants. Studies around the world show that eating plenty of wholegrain cereals reduces the risk of certain types of cancer, heart disease and type 2 diabetes. A new study published in the American Journal of Clinical Nutrition adds to a growing body of evidence. Our results ‘suggest a lower risk of diabetes and heart disease in people who consume diets high in wholegrains’ wrote lead author Majken Jensen from Aarhus University Hospital and Harvard School of Public Health. In this joint Danish-American cross-sectional study, the researchers analysed diet records (assessed by a 131-item food frequency questionnaire) and took blood analyses of 468 men and 473 women to measure intake of whole grains, bran and germ to markers of glycemic control, blood lipids, cholesterol, and inflammation. ‘Compared with participants in the lowest intake group, participants in the highest intake group had lower concentrations of homocysteine, insulin, C-peptide, and leptin. Inverse associations were also observed with total cholesterol, HDL (good) cholesterol, and LDL (bad) cholesterol,’ reported Jensen. No link was observed between the intake of wholegrains and markers of inflammation.
AJCN (vol. 83 pp 275–83)

wholegrains

GI Group: Don’t make the mistake of equating wholegrains with low GI (indeed most wholegrain breakfast cereals and breads have a high GI). You get double the benefit if your wholegrains are also low GI.

By Bread Alone
Back in July 2005 GI News, we reported on Dr Allison Hodge’s study that found that ‘the simple change from white bread to lower-GI bread within a high carbohydrate diet could reduce the risk of diabetes.’ For many people, just swapping bread type ‘may be a more acceptable dietary change than one requiring a whole new eating pattern,’ concluded the researchers who had followed the diets and health records of more than 36,000 men and women in Australia for four years. A small Swedish cross-over study of seven women with impaired glucose tolerance and a history of gestational diabetes published in the European Journal of Clinical Nutrition highlights the real and immediate value of making the switch. ‘A combination of low GI and a high content of cereal dietary fibre has a beneficial effect on insulin economy in women at risk of developing type 2 diabetes,’ wrote lead author Dr Elin Ostman. For the study, the women were given either a specially baked low GI bread that was rich in dietary fibre or high GI, low fibre bread during two consecutive 3-week periods separated by a 3-week washout period. The results were unanimous. Lowering the GI and increasing dietary fibre ‘improved insulin economy as judged from the fact that all women lowered their insulin responses to the intravenous glucose challenge’ wrote Ostman.
EJCN (2006) 60, 334–341

bread

5 comments:

Anonymous said...

your comments against low carb diets are unfair and biased. you cite anecdotical evidence that are really very rare extremes in people that are not doing it right.

1) NO DIET IS REALLY RECOMENDED FOR ILL OR PREGNANT PEOPLE

2) THERE MIGHT HAVE BEEN SOME UNDERLYING HEALTH REASONS FOR THE KETOACIDOSIS YOU MENTION

3) OPPOSERS OF LOW CARB REGIMES TEND TO STICK TO CRITICISM THAT ARE REALLY DIRECTED TO THE SO CALLED "INDUCTION PHASE" WHICH LASTS ONLY TWO WEEKS. AFTER THAT, DIETERS ON ATKINS CAN AND SHOULD CONSUME A GREAT VARIETY OF GREEN, LEAFY NUTRICIOUS VEGETABLES, AMONG MANY OTHERS, LIKE MUSHROOMS, EGGPLANT, PEPPERS, BROCCOLI, CAULIFLOWER, ETC ETC. ATKINS NEVER ENCOURAGES YOU TO EAT ZERO CARBS. 20 GRAMS FRO THE FIRST 2 WEEKS, AND YOU RAISE THOSE LEVELS AFTER THAT

5) IT IS NOT TRUE THAT CONSUMING BAD FATS IS UNAVOIDABLE. YOU CAN AND SHOULD AVOID THEM AND STAY WITHIN ATKINS

6) I LOVE CARBS, I COULD BE HAPPY WITH A GI DIET, AND I WILL RESORT TO IT AS SOON AS I REACH MY GOAL WEIGHT, BUT LOSING WEIGHT WITH GI DIETS IS COMPLICATED BECASUSE AS SOON AS YOU SURPASS THE LEVEL OF CARBS YOU CAN CONSUME, YOU STOP LOSING WEIGHT AND START GAINING.

7) AS SOON AS I CAN START INCORPORATING MORE CARBS INTO MY DIET, THEY WILL BE OF THE LOW GLYCEMIC LOAD KIND.

THERE SHOULD REALLY BE NO QUARREL BETWEEN LOW GLYCEMIC AND ATKINS BECAUSE THEY ARE FUNDAMENTALLY THE SAME. THE DIETS YOU SHOULD BE STRONGLY OPPOSING ARE THE LOW CALORIC AND THE LOW FAT DIETS.

THE TRUTH IS THAT ATKINS WORKS. ONCE YOU GET TO YOUR EQUILIBRIUM LEVEL, THEN YOU CAN DO LOW GL AND STAY IN A NARROW WEIGHT BAND.

THANKS,

PABLO

Anonymous said...

Glad to know there is a real reason I felt so terrible on low carb ... I have hypogycemia! My Glucose levels just can't handle low carb. I can't give up fruit. I believe God gave us a pancreas to handle things like fruit.

One question, how do you know if your whole grain cereal is low GI?

James Krieger said...

I find your article on low-carbohydrate diets to be very biased and unbalanced. Some of the information provided has been shown to be false in scientific studies.

For example, Miller, Powell, and Price comment that the brain "is not at its best using ketones, and mental judgement is impaired." There is no scientific evidence that this is true. The brain adapts quite well to the use of ketones as fuel, to where 80% of its fuel needs can be derived from ketones. Anecdotally, many people report thinking more clearly on a ketogenic diet once they've adapted to ketosis (which takes 1-3 weeks). Ketogenic diets have been used for years as a treatment for epileptic children and reduce their seizures by up to 50%. Ketogenic diets are also being investigated as a possible treatment for Parkinson's disease.

The comment "You lose fat, water, and muscle" is true of ANY diet. My recent meta-regression, published in the February 2006 issue of AJCN, shows quite clearly that fat loss is significantly higher on ketogenic diets, even after control for energy intake. Fat-free mass loss was also greater, but not by a large amount.

I am disappointed in the GI Newsletter's treatment of this topic. I would expect a better, balanced scientific analysis of low-carbohydrate, ketogenic diets.

James Krieger, M.S., M.S.
20/20 Lifestyles Research Associate
PRO Club
http://www.proclub.com
Editor, Journal of Pure Power
http://www.jopp.us

gi group said...

How do you know if your whole grain cereal is low GI? Check out www.glycemicindex.com (click on the database) first to see if the product or brand has been GI tested. If you want a handy pocket guide, the annual New Glucose Revolution Shopper's Guide to GI Values may be helpful. A book that will give you some useful general guidelines for choosing low GI foods is Low GI Eating Made Easy (it includes the top 100 low GI foods and has a large section on cereal grains). If it's breads you are mostly concerned about, our rule of thumb is to suggest people look for really grainy breads, granary, 100% stoneground or wholewheat, sourdough, or breads made from chickpea or other legume based flours such as soy, or with added soybeans. The coarser textured, denser and less processed a bread is, the lower its GI is likely to be. We also suggest that you try people power: get in touch with the manufacturer and ask. Sometimes products have been GI tested but the result not published.

GI Group said...

Responding to feedback on GI.com

In May’s newsletter, we listed the reasons why we advocated a low GI diet rather than a low carbohydrate diet. It’s important that they are not regarded as the same. Some of our readers admonished us for our stance. Here are their comments and our responses.

1) No diet is really recommended for ill or pregnant people.

Pregnant women have to eat and the diet they eat affects their baby’s development. We use the word ‘diet’ in the sense of ‘eating plan’ (as defined by most dictionaries), not restricted energy intake. We agree that it’s not a good idea to restrict energy intake during pregnancy (one reason being the effect of ketones on fetal development). But it’s vitally important that women eat a healthy diet throughout their pregnancy and throughout their reproductive years – not every pregnancy is planned. A low GI diet fits the bill perfectly, a low carbohydrate diet doesn’t (and you appear to agree). If a diet’s not good for a developing fetus, why would it be good for anything else?

2) There might have been some underlying health reasons for the ketoacidosis you mention.

The case of a woman who was hospitalised for life-threatening ketoacidosis was written up in the Lancet in early April (Chen TY, Smith W, Rosenstock JL, Lessnau KD The Lancet - Vol. 367, Issue 9514, 18 March 2006, Page 958). The precipitating factor, whatever her individual vulnerability, was strict adherence to a low carbohydrate diet. Fortunately, most people don’t/can’t adhere strictly to the Atkins diet.

3) Opposers of low carb regimes tend to stick to criticism that are really directed to the so called "induction phase" which lasts only two weeks. After that, dieters on Atkins can and should consume a great variety of green, leafy nutritious vegetables, among many others, like mushrooms, eggplant, peppers, broccoli, cauliflower, etc etc. Atkins never encourages you to eat zero carbs. 20 grams for the first 2 weeks, and you raise those levels after that.

Yes, that’s true, criticism is often aimed at the induction phase but it’s also true that the second phase is also restricted in carbohydrates (~50 g/day) and adherents are encouraged to return to the induction phase (20 g/day) if weight loss slows. Furthermore, because Atkins recognised that the diet was not nutritionally balanced, a vitamin and mineral supplement is compulsory.

The study by Yancy et al (Ann Int Med 2004: 140; 769) compared an Atkins diet with a prudent (low fat but high GI) diet in 120 overweight volunteers. Those following the Atkins diet lost twice as much weight in 24 weeks but read the small print. Specifically, adverse effects occurred more frequently in the low-carbohydrate diet group than in the low-fat diet group, including constipation (68% vs. 35%; P < 0.001), headache (60% vs. 40%; P = 0.03), halitosis (38% vs. 8%; P < 0.001), muscle cramps (35% vs. 7%; P < 0.001), diarrhea (23% vs. 7%; P = 0.02), general weakness (25% vs. 8%; P = 0.01), and rash (13% vs. 0%; P = 0.006). One participant sought medical attention for constipation but had no complications. One 53-year-old man in the low-carbohydrate diet group developed chest pain near the end of the study, and coronary heart disease was subsequently diagnosed.

Moreover, in a similar study by Stern and colleagues (Ann Int Med 2004; 140: 778), two persons on the low carbohydrate diet died, and a third was hospitalized. No such adverse events were recorded in those following the high carbohydrate diet.

5) It is not true that consuming bad fats is unavoidable. You can and should avoid them and stay within Atkins.

If carbohydrates occupy only 10% of your energy intake (ie you eat about 50 g of carbohydrates per day), then the other 90% of energy must come from a mix of protein and fat. The upper limit on protein intake by humans is ~40% of their calories because of limits on the liver’s capacity to produce urea. By a process of deduction, that means more than 50% (and more often than not 60%) of energy comes from fat. Even if you ate a perfectly healthy balanced diet with a P:M:S ratio of 1:1:1, you’d be consuming about 20% of your calories as saturated fat. The recommendation is less than 10%.

6) I love carbs, I could be happy with a GI diet, and I will resort to it as soon as I reach my goal weight, but losing weight with GI diets is complicated because as soon as you surpass the level of carbs you can consume, you stop losing weight and start gaining.

That was the claim Atkins made but he had no scientific evidence to back that. To my knowledge, there’s still no evidence. Indeed, recent studies suggest that people find it very hard to stick to a diet with so little carbohydrate (too much discipline is needed) and eventually re-gain the weight they lost. Is there any point in losing weight and then re-gaining it? Wouldn’t it be better to align food habits with something that’s not only healthy, helps you lose weight and keep it off for good?

7) As soon as I can start incorporating more carbs into my diet, they will be of the low glycemic load kind.

That’s good. Why not cut to the chase early?

8) There should really be no quarrel between low glycemic and Atkins because they are fundamentally the same. The diets you should be strongly opposing are the low caloric and the low fat diets.

No, that’s incorrect. Atkins wants to ditch carbs, low GI diets can be moderately or even very high in carbs, but of the low GI kind. If Atkins had known what we know now, he would have seen ways to lower insulin levels without cutting out the carbs out altogether. He recognised that high insulin levels interfered with weight control, but he did not have sufficient knowledge to work out the best way to lower them. Remember he had no training in nutrition.

9) The truth is that Atkins works. Once you get to your equilibrium level, then you can do low GL and stay in a narrow weight band.

Yes, we agree that Atkins works in the short term. But not the long term. So what’s the point in following such a diet?