Chocolate for breakfast may help fat burning

Executive summary

* A study was published, which was press-released with the claim "consuming milk chocolate may be a fat-burner in postmenopausal women."

* The study was a very small, randomised, crossover, trial involving 19 postmenopausal women. Any findings would not necessarily apply to any non-postmenopausal woman.

* There were two interventions. One involved consuming 100g of milk chocolate within an hour of waking and the other involved consuming 100g of milk chocolate within an hour of bedtime. There was also a control, which involved consuming no chocolate. As it was a crossover trial, all 19 women completed all phases. Each phase was 14 days long.

* The key results claimed were:

1) The women did not gain weight;

2) Eating chocolate in the morning increased fat being burned as fuel. Eating chocolate in the evening increased carbohydrate being burned as fuel.

* Claim (1) was highly misleading. While the 19 women averaged together did not collectively gain weight – individually, women gained or lost weight in each phase of the study. Substantial adjustment of intake of non-chocolate calories took place. Unsurprisingly (postmenopausal) women don't want to gain weight.

* Claim (2) was highly misleading. i) Fat or carbohydrate burning changed relative to morning or evening chocolate consumption. Neither changed relative to the control. ii) People think that fat burning means body fat burning i.e., weight loss, but it doesn’t necessarily mean this. In this study it is highly likely that women were burning the chocolate fat that they had just consumed.

* Randomised controlled trials are supposed to provide a high level of evidence. This trial left one wondering why postmenopausal women? Why not control for other calories? Or at least provide data on these? What was the point of all this?