Obesity is a major health problem for Western nations because being overweight is associated with the development of a number of diseases such as diabetes, arthritis and cardiovascular disease. The cost associated with treating these diseases is increasing as the epidemic of obesity spreads throughout all age and socioeconomic groups. Recommendations from medical sources are for those with high body mass indexes and excess body fat to lose weight, through calorie restriction and exercise. However, beyond this advice, little information is given to help those affected. In addition, many people feel psychological pressure from mainstream media sources, to conform to an ideal body shape. The result is that large proportions of the populations of Western nations are currently attempting to lose weight, and diet books and products have become big business.
Weight gain and obesity is not fully understood, and it is at present unclear as to the most effective way to reverse this process and cause weight loss. Evidence suggests that simple calorific restriction and exercise is an effective short-term tool against weight gain, but questions remain about its long term success. Other factors such as insulin resistance, mineral deficiencies (such as chromium) and hormones (such as leptin and ghrelin) appear to be important variables but their exact role and possible interactions are not clear. In addition, the long term health implications of many calorie restrictive diets have not been assessed, and so it is unclear as to their ability to supply adequate micronutrient intakes. Micronutrient deficiency is serious as it can complicate obesity related health concerns and may increase the likelihood of developing further health problems.
To investigate the effects calorie restriction on micronutrient levels, researchers1 used dietary recall to assess the vitamin and mineral intakes of a number of individuals on commercially available calorie restrictive diets. Overweight and obese subjects were assigned to either the Atkins diet, the Zone diet, the LEARN diet or the Ornish diet. At 8 weeks, energy intakes had reduced for all groups, but micronutrient levels had also dropped to levels that might be associated with risk of inadequacy in three of the dietary regimens. In the Atkins diet group levels of thiamine, folic acid, vitamin C iron and magnesium; in the LEARN diet group levels of vitamin E, thiamine and magnesium; and in the Ornish diet group levels of vitamin E, B12 and zinc, were found to be inadequate. However, the Zone diet group showed no signs of inadequacy, but managed to increase intakes of vitamin A, E, K and C.
Restricting intakes of foods is an effective way to decrease calorific values of meals, but focussing solely on macronutrient intakes can compromise intakes of micronutrients. In the above cited study, 3 out of 4 of the diet programmes resulted in micronutrient inadequacies that have to potential to develop into serious ill health. Only the Zone diet provided adequate micronutrient levels. In the Atkins diet, LEARN diet, Zone diet and Ornish diet 36, 29, 34 and 31 % of participants were taking multivitamin and mineral supplements, respectively. However, calorie restriction still caused inadequacies of certain micronutrient. Those wishing to maintain optimum health while losing body fat should therefore consider the supplementation of a strong, high quality multivitamin and mineral in addition to high quality micronutrient dense food. Additional vitamins and minerals should be supplemented where appropriate on an individual basis.
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