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Limited evidenceMyth check

Some foods burn fat (green tea, chilli, grapefruit, 'negative-calorie' foods)

No food melts body fat. Green tea had no meaningful effect on weight in trials outside Japan, and chilli compounds trim a few dozen calories from the next meal at most. Foods help fat loss indirectly: whole, minimally processed foods with protein and fibre make it easier to eat less without feeling deprived.

What the science says

  • Green tea makes you lose weight Limited evidence

    The 2012 Cochrane review by Jurgens and colleagues pooled six trials conducted outside Japan (532 participants): green tea preparations changed weight by -0.04 kg versus control, essentially zero. Japanese trials were too heterogeneous to pool and reported small losses.

  • Chilli (capsaicin) burns meaningful fat Limited evidence

    Whiting and colleagues' 2014 meta-analysis found capsaicinoids before a meal reduced intake at that meal by about 74 kcal, with high heterogeneity and short studies. That is a small effect on intake, not fat burning, and long-term weight trials are lacking.

  • Minimally processed foods help you eat less Moderate evidence

    Hall and colleagues (2019) fed 20 adults ultra-processed or unprocessed diets for 2 weeks each, matched for presented calories and nutrients, eating as much as they wanted. They ate about 508 kcal/day more on the ultra-processed diet and gained 0.9 kg, and lost 0.9 kg on the unprocessed diet. Food choice matters through how much you eat.

What to do instead

Build meals around protein, vegetables, fruit, legumes and whole grains to make a calorie deficit easier, and enjoy green tea or chilli for their taste rather than as fat burners.

Protein at each mealA palm-sized portion (about 25–40 g protein)
Vegetables and fruitHalf the plate at main meals
Ultra-processed snacks and drinksLimit; they make overeating easy
Green tea, chilli, vinegar, grapefruitFine to include; expect no meaningful fat loss from them

Who should be careful

Concentrated green tea extracts have been linked to liver injury; whole foods are not a concern for healthy adults. Grapefruit interacts with several medications, so check with a pharmacist or physician if you take any. People with diabetes, heart, kidney or thyroid conditions, anyone with a history of an eating disorder, and anyone pregnant or considering weight-loss medication should plan weight loss with a physician or registered dietitian rather than on their own.

Frequently asked questions

Does green tea help me lose weight?

In trials outside Japan it changed weight by -0.04 kg versus control, essentially no effect.

Does spicy food speed up fat loss?

Capsaicinoids reduced intake at the next meal by about 74 kcal in a meta-analysis, a small effect without long-term weight data.

So which foods help?

Minimally processed foods: in a 2019 trial people ate about 508 kcal/day less on an unprocessed diet than on an ultra-processed one.

Scientific references

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