Far from piling on the pounds, a chocolate habit can help keep you slim, new research suggests.
Just in time for Easter, scientists have announced the discovery every chocolate lover has been waiting for.
A study has found that, despite boosting calorie intake, regular chocolate consumption is related to lower body mass index (BMI).
The effect is modest but greater than can be explained by chance, say the US researchers who took account of influencing factors such as overall fat consumption and exercise.
BMI relates height and weight and is the standard measurement used to assess levels of obesity.
The good news about chocolate emerged after scientists screened a group of 972 men and women with an average age of 57 for a study of statins - cholesterol-lowering drugs.
Among other diet and lifestyle questions, participants were asked: "How many times a week do you consume chocolate?"
Chocolate is known to contain plant chemicals called polyphenols that combat heart disease and may influence metabolism.
The researchers suspected they might, to some extent at least, off-set the unwelcome effects of high saturated fat levels in chocolate bars and sweets.
No account was taken of different types of chocolate, some of which contain more healthy elements than others.
The results showed that chocolate was not only "calorie neutral" but actually appeared to make people slimmer.
Participants who ate chocolate on more days of the week than average were statistically likely to have a lower BMI than those who did not.
This was despite the fact that people who ate more chocolate did not consume fewer calories overall, or take more exercise.
In fact they ate more - chocolate consumption was associated with greater overall saturated fat intake.
Volunteers had an average BMI of 28 - meaning they were overweight - and ate chocolate on average twice a week. No link was seen between the amount of chocolate eaten and either higher or lower BMI.
The findings appear in Archives of Internal Medicine, published by the Journal of the American Medical Association.
Study leader Dr Beatrice Golomb, from the University of California at San Diego, said: "Our findings appear to add to a body of information suggesting that the composition of calories, not just the number of them, matters for determining their ultimate impact on weight.
"In the case of chocolate, this is good news - both for those who have a regular chocolate habit, and those who may wish to start one."
The scientists pointed out that chocolate products "are often rich in sugar and fat, contributing to assumptions that chocolate boosts BMI".
They added: "This study does not obviate the possibility that some chocolate-containing products do so, that some chocolate consumption profiles do so, or that for some people, even frequent modest chocolate consumption does so.
"Moreover, since findings are cross-sectional, causality in the observed association cannot be assumed. However, the finding fits with the literature suggesting benefits of chocolate for other metabolic factors."
Previous research on rodents has suggested that chemicals in chocolate might speed up metabolism.
One chemical derived from the chocolate ingredient cocoa, epicatechin, has been shown to boost numbers of mitochondria, the cell's energy-generating "power houses". Mitochondria burn up calories.
Epicatechin reduced weight in rats whose calorie intake and exercise levels were unchanged.
"Parallel processes in humans, if present, could underlie our findings," Dr Golomb's team concluded in their research article.
The results justified a randomised trial looking at the metabolic benefits of chocolate in humans, said the scientists.