|Title||Dietary Supplements for Improving Body Composition and Reducing Body Weight: Where is the evidence?|
|Publication Type||Journal Article|
|Year of Publication||2012|
|Journal||International journal of sport nutrition and exercise metabolism|
|Date Published||2012 Feb 15|
Weight loss supplements typically fall into one of four categories depending on their hypothesized mechanism of action. These four categories are as follows: 1) products that block the absorption of fat or carbohydrate, 2) stimulants that increase thermogenesis, 3) products that change metabolism and improve body composition, and 4) products that suppress appetite or give a sense of fullness. Each category is reviewed and an overview of the current science related to their effectiveness is presented. While some weight loss supplements produce modest effects (<2kg weight loss), many have either no or few randomized clinical trials examining their effectiveness. A number of factors confound research results associated with the efficacy of weight loss supplements, such as small sample sizes, short intervention periods, little or no follow-up, and whether the supplement is given in combination with an energy restricted diet or increased exercise expenditure. There is no strong research evidence indicating that one specific supplement will produce significant weight loss (>2kg), especially long-term. Some foods or supplements, such as green tea, fiber and calcium supplements/dairy products, may complement a healthy lifestyle to produce small weight losses and/or prevent weight gain over time. Weight loss supplements containing metabolic stimulants (e.g. caffeine, ephedra, synephrine) are most likely to produce adverse side effects and should be avoided.