Dr Ingrid van Heerden, Health24's DietDoc, was commissioned by the Association for Dietetics in South Africa (ADSA) to undertake a study of scientific publications to determine the weight-loss and health effects of high-protein, high-fat, very-low-carbohydrate diets.
With regards to the Atkins Diet, the following facts were published: The high-protein, high-fat Diet Revolution described by Dr Robert Atkins in many of his books is a popular weight-reduction diet. Overweight or obese people often turn to the Atkins Diet because it promises rapid weight loss. The large amounts of protein and animal fat in this diet are, however, potentially harmful to health, which is why South African dieticians are concerned about its use.
Recent scientific studies on the Atkins Diet seem to have proved that this diet doesn't have a negative effect on blood-fat levels and can actually lower some blood fats, which are called triglycerides. Other evidence suggests that the diet can improve insulin resistance. Supporters of the Atkins Diet have hailed these results as proof that the diet is safe and can be used by everyone for long periods of time.
The actual situation is somewhat different. The research studies, some of which were funded by Atkins Nutritionals, who control the sale of the Atkins diet books and high-fat foods, have managed to answer some of the questions related to this diet, but there are as yet too few of these studies and not enough long-term studies to draw proper conclusions.
Questions that were answered include the following:
Does the Atkins Diet cause rapid weight loss?
Yes, it does. This is due to four factors:
Atkins dieters reduce their energy intake by as much as 500 kcal (2100 kJ) a day. Energy reduction will usually result in weight loss, so the Atkins Diet is not unique in this respect.
Most of the weight loss is due to losses of body water and glycogen (the form in which carbohydrates are stored in the body), and will be regained rapidly.
The condition of ketosis, which is induced by the high-fat content of the diet, has an appetite-suppressing effect, but such an effect can also be achieved by eating a high-fibre diet.
Protein foods are more satiating than low-fibre carbohydrate foods, but this is no reason for eating high-fat protein foods. A moderate increase in lean protein intake combined with high-fibre carbohydrates with a low glycaemic index will also prevent hunger.
Does the Atkins Diet result in permanent weight loss?
No, it doesn't.
Studies that followed dieters for one year found that the majority had regained most of the weight they had initially lost. The Atkins Diet is, therefore, not a permanent solution to obesity.
In addition, rapid weight loss followed by regain could cause the "yo-yo-effect", which makes it increasingly difficult to lose weight every time you try to diet.
A more permanent solution is to change your lifestyle, to eat low-fat, high-fibre foods, including plenty of fruit and vegetables, unprocessed grains and cereals, and legumes, and to exercise regularly. Such lifestyle changes will result in weight loss, an improvement in overall health, and prevent degenerative diseases.
Is the Atkins Diet easy to stick to?
No, it's not.
Up to 43% of the dieters in the studies dropped out and many of them cheated.
Does the Atkins Diet improve blood-fat levels and protect against heart disease?
We can’t really say with conviction if it does or doesn't.
Most of the studies were short, so we don’t know what the long-term effects of very high fat intakes will be on blood-fat levels and the risk of heart disease.
The studies did show that the Atkins Diet lowered triglyceride levels, but the results for other important blood fats (total cholesterol and other types of cholesterol) were not better than results obtained with conventional weight-reduction diets (i.e. energy-reduced or low-fat diets).
Scientists suspect that the drop in triglyceride levels is caused by weight loss, so any diet that produces weight loss will improve triglyceride levels. The jury is still out on this one.
Does the Atkins Diet improve insulin resistance?
But the Atkins Diet is not unique in this respect. Other more balanced, low-fat diets with a low glycaemic index will achieve the same results.
Is the Atkins Diet harmful?
We don’t know yet.
Many other research studies have repeatedly indicated that high protein and high fat intakes can cause kidney stones and kidney disease, particularly in diabetics, and increase the risk of cancer, gout, arthritis, and other blood-fat problems.
Dr Atkins suggested that individuals using his diet should have their uric acid levels tested and take medication to prevent gout as a routine precaution. The dehydrating effect of such diets can be particularly harmful to athletes if they exercise strenuously while cutting out carbohydrates completely.
Another problem associated with the diet is its lack of protective nutrients such as vitamins, minerals, bioflavonoids, and dietary fibre, which can cause serious nutritional deficiencies and constipation. Even Dr Atkins realised that his diet "for life" was so deficient in protective nutrients that he recommended that anyone using the Atkins Diet Revolution should take vitamin and mineral supplements on a daily basis.
Are dieticians concerned about the potential dangers of the Atkins Diet?
South African dieticians are concerned by the lack of conclusive scientific evidence of the long-term safety and efficacy of the Atkins Diet.
Recent media reports indicate that even representatives of Atkins Nutritionals are urging the public to cut down on the amount of fat they eat when using this diet, to switch to lean proteins, and not to gorge themselves on high-fat foods.
This turnaround is probably in reaction to unfavourable media reports stating that Atkins dieters have experienced dramatic increases in blood cholesterol levels, necessitating surgery, or such severe constipation that they were hospitalised.
What is ADSA doing about the Atkins Diet problem?
Suggesting safe alternatives.
ADSA urges the public to be careful not to fall into the trap of believing that the Atkins and other high-protein, high-fat diets are magic solutions to permanent weight loss.
If you need to lose weight, ADSA recommends the use of an energy-reduced, balanced, low-fat diet, rich in protective nutrients, dietary fibre and foods with a low glycaemic index. Such diets can be used successfully for the rest of your life and will also protect you against heart disease, certain types of cancer and other diseases of lifestyle. By combining such diets with regular exercise, you'll not only lose weight and keep it off, but also improve your health and wellbeing.
If in doubt about what diet you can use to lose weight safely, contact your nearest dietician for advice. You can find a list of dieticians in your area on ADSA's website.
- (Dr Ingrid van Heerden, DietDoc, updated November 2008)