S J Stear

Without doubt, physique, including body mass or composition, size and shape, has an important role to play in optimising sports performance. Size does matter! Consequently, various strategies, including dietary intervention, are employed in an effort to influence physique. Fundamentally, body weight (body mass) is lost when dietary energy (energy intake) is consumed at a level less than daily requirements (energy expenditure), with an energy deficit ∼10–20% being both effective in producing loss and being tolerated over the longer term. However, although any strategy, including popular/fad diets, that reduces energy intake below expenditure will result in weight loss, most athletes need to achieve a more specific goal of promoting loss of body fat while maintaining lean body mass and optimising sports performance. Therefore, athletes embarking on an energy-reduction programme should do so only under the guidance of a sports nutrition professional. This will ensure that the intakes of important macronutrients and micronutrients are not detrimentally compromised and that the energy intake is sufficient to support their training/competition needs. Although there is growing evidence of a positive role for dairy/calcium intake in assisting weight/fat loss, this has not yet been extensively studied in the athletic population.

In the multibillion dollar supplement industry, ‘weight loss’ supplements contribute a significant proportion. A huge range of supplements claims to enhance sports performance by affecting body composition—either by increasing muscle mass and/or reducing body fat. Supplements in the broad ‘weight loss’ category include caffeine, l-carnitine, chromium picolinate, CLA (conjugated linoleic acid), dairy/calcium supplements, HMB …