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In defence of low carb diets |
Editor
I was concerned that Dr Andrew Binns’s dismissal of the low carbohydrate ( The fashionable zone diet (February 2001) may deprive many of tangible benefits). It would seem that many who have failed to make progress with other more traditional methods have made good progress on the low carbohydrate diet. I certainly make no pretensions to having much knowledge of dietetics and my interest largely relates to gestational diabetics, patients with polycystic ovaries many of whom have insulin resistance associated with their obesity, and obese patients contemplating gynaecological surgery.
The ‘low carb’ concept introduced by Dr Atkins has suffered as a result of his own hardline attitude and the entrenched philosophies of admittedly formidable organisations such as the heart associations, the NHMRC and GutBusters with whom Andrew has a considerable and continuing association. Further damage to the concept will be done by branding it as the ‘Hollywood Diet’ and its adoption by many of the LA glitterati.
Despite all this it may be that Dr Atkins had more than the germ of an idea and one that has been rationalised by others since then including the Hellers with their various contributions about carbohydrate addiction and Donna Aston’s Fat or Fiction.
Sydney dietician Jill McGregor points out that people on the diet feel that they have more sustained energy throughout the day with none of the highs and lows associated with high carbohydrate diets. The most common traditional dietary recommendations are for a high carbohydrate, low fat diet with bread, pasta, rice and fruit allowed in liberal quantities. These diets have proved spectacularly unsuccessful particularly in the long term and the virtual epidemic of carbohydrate intolerance in western society is probably related to excessive dietary carbohydrate.
It is acknowledged that the low carbohydrate diet may be nutritionally imperfect and overall lacking in fibre so that supplements may be required for a time while the individual re-evaluates carbohydrate threshold. The reality for many seems to be that during this short time frame considerable weight loss is achieved and that this can be maintained long term even after the re-introduction of a more considered amount of nutritious and fibre-providing high carbohydrate foods than formerly might have been the case.
Brendan O’Sullivan is an obstetrician & gynaecologist based in Lismore, NSW, Australia.
Ed note: Dr Garry Egger responds to this letter in an article below called Low carb diet not recommended by any existing national clinical guidelines. He is the founder and scientific director of the GutBuster program, Adjunct Professor of Health Sciences, Deakin University, and an NH&MRC committee member currently developing clinical guidelines on obesity for Australia.
Low carb diet not recommended by any existing national clinical guidelines
In a letter to the editor, Dr Brendan O’Sullivan has espoused the benefits of the low carbohydrate diet at the expense of a low fat eating program promoted for weight loss, thus questioning programs such as the GutBuster program. As the developer of this program and a medical educator in obesity, I feel this requires a reasoned response for medical practitioners to avoid throwing out the baby with the bathwater.
Dr O’Sullivan is right to suggest the low carb diet is a resurrection of the Atkins diet, which was discredited more than 25 years ago. In hindsight it is obvious that this is with good reason. However, before this is spelt out, it is important to stress that fad diets come and go, usually not lasting more than 6-12 months. There is a very good reason for this and that is that any reduction in total energy - whether through carbohydrate, protein or fat - resulting in a negative energy balance will result in weight loss over the short term. However, it is now well accepted amongst obesity researchers that weight loss for less than 12 months is not regarded as effective. Anyone can lose weight. Keeping it off is a different matter. The low carbohydrate diet fails in this latter category.
Although all ‘diets’ should be condemned (because they can’t be maintained) the low carb diet has particular problems and can be argued against on several different levels. In the first instance, carbohydrate is the most accessible form of energy. While one dietitian may claim that a low carbohydrate diet provides ‘more energy’, there is ample evidence that over the long term, it will increase lethargy and result in a decrease in energy and hence ability to carry out that which has the most long term benefit for weight loss, ie. regular physical activity. It requires more energy to store carbohydrate as fat in the body (25%) than it does to save fat as fat (3%). Fat is also known to be less satiating and lead to passive over-consumption. A diet that is high in fat (and many high protein and/or low carbohydrate diets qualify here because fat is often more accessible in animal protein) can lead to dyslipidaemia in individuals prone to this.
One also has to look to expert opinion. Of the four sets of national clinical guidelines for obesity currently in existence throughout the world, none recommend a low carbohydrate diet, while all recommend a low fat pattern of eating. As an NH&MRC committee member currently developing guidelines for Australia, I can guarantee that we will follow suit on the basis of scientific evidence. It’s appropriate also to note that at no international conferences on obesity have any low carbohydrate diet exponents ever appeared to present their evidence for this – despite an open invitation to do so from the International Association for the Study of Obesity. Finally, in the US Weight Control Registry, a highly respected research outlet on long term weight loss losers, it is relevant to note (Am J Clin Nutr) that almost all those who have lost weight and maintained this over five years have done so through a low fat eating plan. Virtually none have used a low carbohydrate diet.
Dr O’Sullivan is wrong to suggest that low fat eating (not a diet per se) has proved “spectacularly unsuccessful”. At the individual level they are slower to work than the low carb approach where weight loss is an immediate outcome (because of the fluid loss from reducing carbohydrate), but of much greater success over the long term. If Dr O’Sullivan is using obesity at the population level and self reported fat intake as a measure of lack of success (as has been claimed by some in the US), he would do well to note that despite the claims in dietary questionnaires that fat has been decreasing in the American diet, this is only relative to total food intake. A recent paper by Dr Bob Jeffreys’s group at Minnesota has shown using food disappearance data, that carbohydrate consumption (and total energy) in the US has increased by 35% from 1970-94, while fat consumption has increased by only 5%. Nobody would ever suggest that total energy is not an issue in obesity whether it comes from carbohydrate or fat!
As misinformation in weight control is more counter-productive than in many other fields of health, it is incumbent upon the medical profession to avoid the traps of popularism. I hope the new Australian clinical guidelines on obesity due out later this year will help medical practitioners in this respect.
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