Weight-loss supplements typically fall into 1 of 4 categories depending on their hypothesized mechanism
of action: products that block the absorption of fat or carbohydrate, stimulants that increase thermogenesis,
products that change metabolism and improve body composition, and 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 (2 kg), especially in the long term. Some
foods or supplements such as green tea, fiber, and calcium supplements or dairy products may complement
a healthy lifestyle to produce small weight losses 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.