Weight loss occurs with low energy diets and this weight loss includes large amounts, perhaps as high as 50 %, of skeletal muscle. As skeletal muscle determines resting metabolic rate, this loss of skeletal muscle reduces the resting metabolic rate semi-permanently, and this damage can possibly last for decades or more. Based on evidence from the scientific literature, anyone who has followed a low energy diet to lose weight will almost certainly have damaged their metabolism in this way. The result of a lowered resting metabolic rate is a reduction in the requirement for energy, and this increases significantly the risk of gaining weight in the future. Those who have been through cycles of weight loss are the most at risk for future weight gain because they have damaged their metabolism through this cyclical loss of muscle mass. Trying to lose body fat while in such a state of metabolic dysfunction is factors of magnitude more difficult than for a healthy metabolically normal individual.
Body composition improvements are composed of two principal changes. One of the changes is a loss of body fat and the other is a gain in muscle tissue. There is a cultural preoccupation with the former, and a cultural opposition, particularly amongst women, towards the latter. However, it is the contention of this author that the latter, skeletal muscle increases, is a pivotal, if not the pivotal factor in improved body composition. Increases in skeletal muscle are a primary cause of fat loss as they increase the energy requirements of the body which creates a milieu interior in which energy oxidation is more likely. As resistance training is the best way to increase skeletal muscle, resistance training is therefore one of the best ways to lose body fat. Supplements that aid this process by facilitating increases in lean mass are therefore beneficial to overall body composition and should be considered by the female athlete, who due to hormonal conditions may find muscle gain more difficult that a male counterpart.
Chromium is a trace mineral required for the correct function of the insulin system. Deficiencies of chromium may impair insulin sensitivity and thus impede fat oxidation and muscle hypertrophy. The ability of chromium picolinate, an absorbable form of chromium, to improve the body composition of female athletes was demonstrated in a study investigating the effects of resistance training on untrained subjects1 Following 12 weeks of resistance training, the female athletes taking 200 μg chromium picolinate gained 1.9 kg of body weight more than female athletes not taking chromium supplements. This weight was likely largely skeletal muscle, based on muscle circumference increases and skinfold thickness reductions. Skinfold thickness decreased from 59.5 to 55.3 mm (based on summation of tricep, suprailiac and thigh measurements) and the circumference measurements increased from 153.8 to 156.8 cm (based on summation of the chest, thigh and arm).
However, the effects of chromium on body composition improvements in general are controversial, and this relates largely to the fact that researchers do not understand nutritional principles. For example, in this study the male athletes did not obtain the same gains in strength and improvements in body composition from consumption of the chromium. Other studies have also failed to find beneficial effects. This relates to two assumptions made by researchers which show a lack of understanding on mineral biochemistry. Firstly, they assume that the minerals are required in a one-size-fits-all dose, rather than an amount per body weight and relating to the actual mineral metabolism of the individual. The 200 μg chromium supplement may for example have been insufficient for the requirements of the male athletes in this study. Secondly, they assume that mineral have drug like effects. Whereas in reality, a mineral replete individual is unlikely to show the same benefits as a mineral deficient individual.
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