The National Agency for Food, Environmental and Occupational Health Safety (ANSES) – the French public health body – comes to this conclusion¹ following an in-depth analysis of 15 regimes², including those of D^r Atkins, Weight Watchers, Montignac, and the Mayo Clinic.

Whether they advocate a diet reduced in fat, sugar, fruits and vegetables or proteins, these diets induce, according to researchers, “dangerous” dietary imbalances due to excess or lack of nutrients.

Protein, fat, carbohydrate and fiber

• More than 80% of these diets have intakes³ in protein higher than recommended, i.e. 0,83 g per kg (of body weight) per day (g / kg / d). The Atkins, Dukan and Fricker diets are considered high protein because they offer more than twice the recommended intake.
• More than half of the diets offer lipid intakes greater than 90 g per day, which is in the high range of what is recommended (or 35% to 40% of the daily calorie intake). The Atkins, Miami, Cohen and Montignac diets approach or even exceed 50%. The Ornish and Lemon Detox diets are the lowest in fat.
• The situation is not much better when it comes to carbohydrates. Almost all of the diets offer insufficient intakes. The Ornish and Weight Watchers diets exceed the norm.
• In 74% of the diets, fiber intakes are lower than the recommended intake of 25 g per day. This is particularly the case with the Atkins, Mayo and Scarsdale diets.

Iron, calcium, sodium and vitamins

• The recommended dietary iron intake for women (16 mg per day) is rarely achieved.
• Some diets (Scarsdale, Mayo, Montignac, Atkins) do not cover the daily calcium requirements which are established at 900 mg per day.
• Sodium intakes are above the WHO recommended limit (2 mg of sodium) for 000 of the 10 diets studied, including Weight Watchers and Atkins. The Dukan diet is the worst in this regard, offering more than double the limit.
• When it comes to vitamins, the results are varied. Half of the diets have vitamin C intakes below the recommended 110 mg / d. For vitamins D and E, more than 75% of the diets do not reach the recommended intakes (5 ug / d and 12 mg / d respectively). This is the case, among others, of the Montignac, Atkins and Mayo diets.

Other health effects

Beyond the excess or lack of nutrients, these weight loss diets are not without danger. ANSES cites the risks of fractures linked to a loss of bone mineral mass. This is a consequence of insufficient consumption of calcium and lipids.

The risk of gallstones with very low-calorie diets (eg: Atkins, Weight Watchers), as well as colorectal cancer with diets low in carbohydrates and fiber, is present, stress the authors of the report. Very low calorie diets can also have harmful effects on the cardiovascular level by inducing accidents with sudden death. Excess salt is involved in many cardiovascular diseases.

It should be noted that studies have already shown that 80% of subjects regain weight in 1 year and this proportion increases in the long term. Depression and loss of self-esteem are also frequent psychological consequences of repeated diet failures.

In conclusion, the authors of the report affirm that “the search for weight loss without formal medical indication carries risks, in particular when one calls for unbalanced and undiversified dietary practices”. The management of a weight loss application for people suffering from excess weight or obesity must be made by a specialist in order to choose the best diet adapted to the patient. Ultimately, nothing beats a healthy, diverse diet and physical activity to avoid extra pounds.

Louis M. Gagné – PasseportSanté.net

1 To consult the report: www.afssa.fr/Documents/NUT2009sa0099.pdf.

2. The plans studied by ANSES were selected on the basis of their popularity, ie the most frequently cited on the Internet or those corresponding to the most sold books in stores or online. These are the Dr Atkins Diet, Dr Guttersen’s California Diet, Lemon Detox Diet, Dr Delabos’ Chrononutrition Diet, Dr Cohen’s Diet, Dr Dukan’s Diet, Dr Fricker’s Diet, Mayo Diet, Dr Agatston’s Miami Diet, Montignac Diet, Dr Ornish Diet, Dr Tarnower’s Scarsdale Diet, Cabbage Soup Diet, Weight Watchers Diet, and Mr Sears’ Zone Diet. Some of these diets have more than one version.

3. The recommended intakes are those prevalent in France.