The list of over-the-counter dietary and weight loss supplements is exhaustive, with the majority based on scant supporting evidence from studies conducted in humans to support their claims.
Weight-loss products make up one of the largest growing markets in the world. While the Therapeutic Goods Administration is cracking down on the claims associated with complementary medicines, only about one-fifth are evaluated for compliance each year.
Here I’ve evaluated some of the most commonly used products for weight loss for their effectiveness (but not necessarily safety).
Guarana is high in caffeine and derived from the seeds of a South American tree. A short-term double-blinded randomised controlled study (the gold standard of trials where a treatment is tested relative to a placebo) was conducted over eight weeks.
It showed a herbal combination of guarana and Ma Huang (a medicinal preparation from the plant Ephedra sinica) to be effective for weight loss (-4.0kg versus -0.8kg for placebo) and fat loss.
However, despite its proven efficacy for short-term weight loss, its safety is questioned. In 2004, the Food and Drug Administration banned ephedra. The supplement continues to be sold today, but without the active ingredient (alkaloid) ephedra.
Instead, products are now sold with ephedra extract, which lacks the potent ingredient for weight-loss efficacy. Guarana as a stand-alone herbal substance is not proven for weight-loss efficacy.
Acai berry is a fruit, which like many other fruits is packed full of vitamins and minerals and antioxidants. However, it has not been proven to aid with weight loss.
Watch: An easy, delicious and healthy quinoa recipe from Paper Tiger. (Post continues after video.)
Aloe vera is a plant that has been used for centuries, traditionally for wounds and burns. It has laxative properties and at high doses can cause serious side effects. Manufacturers often tout its use as a weight-loss treatment.
There has been one short-term double-blinded randomised controlled study conducted in humans. Despite a significant difference in weight loss between the Aloe vera and placebo group (favouring the Aloe vera group) at the end of the eight-week study, the weight loss achieved by the Aloe vera group was not clinically significant (-0.4kg weight loss versus 0.2kg weight gain for the placebo group).
Caffeine is found in the leaves and fruits of specific plants. It is a stimulant and excessive consumption can cause short-term increases in blood pressure and heart rate. Caffeine increases the amount of energy we burn at rest and increases fatty acid turnover, but most of the mobilised free fatty acids are converted back to their storage form and clinically meaningful weight loss is not achieved.