Fat burners and slimming products: what the research says

Of the 315 trials on 14 products, only 52 counted as good enough and free of major flaws, and only 16 of those showed a difference in weight.^[1]

A second analysis of 67 trials found statistical differences for some substances. None of the pooled substances reached the threshold the researchers had set as clinically meaningful. Single studies above it remain unconfirmed.^[3]

“Glucomannan in the context of an energy restricted diet contributes to weight loss”. This may only be used with 1 g of glucomannan per serving, with the note about 3 g a day in three servings with 1 to 2 glasses of water before meals and as part of an energy-restricted diet.^[6]

A warning about choking with swallowing difficulties or too little fluid is also required.^[6] Reported side effects were abdominal discomfort, diarrhoea and constipation.^[7] Without the energy-restricted diet, the claim does not apply.

• Hidden drugs: From 2007 to 2016, the US FDA found undeclared active ingredients in 776 products. 317 of them were slimming products, and 269 of those contained sibutramine, an appetite suppressant taken off the market.^[9]
• Liver: Green tea extract and mixed products are among the most common triggers of liver injury from products.^[8]
• Eating disorders: In a study of 10,058 young women in the US, those who took diet pills were clearly more likely to have an eating disorder identified for the first time within 1 to 3 years.^[10] This shows a link, not a cause.

Weight loss comes from a calorie deficit that suits you. Protein, fibre, movement and sleep are better supported than any powder.

If food, weight or numbers weigh on you, that is not a case for a product. You will find places to turn to under When to get medical advice and at the BIÖG helpline in Germany.^[11]