Recent research showing a link between moderate chocolate consumption and body mass index has received wide spread coverage in the news (see New Zealand examples here, here and here). But will eating chocolate actually lead to weight loss? The science isn’t that simple writes Justin Norrie, editor of the science news and analysis site The Conversation (reproduced under creative commons, original here):
Are regular chocolate eaters really thinner?
People who eat chocolate on a regular basis tend to be thinner, even when they do not exercise more often, a new study claims.
But health experts have warned that the findings of the study, published today in the journal Archives of Internal Medicine, do not establish a direct link between the consumption of chocolate, which is high in calories and saturated fats, and a low body mass index (BMI).
Merlin Thomas, Adjunct Professor of Preventive Medicine at Baker IDI Heart & Diabetes Institute, said: “In excess, chocolate will induce weight gain. It will induce obesity, hypertension, diabetes, heart disease and an early demise. But then again, so will any overindulgence.”
A research team from the University of California, San Diego, found that among about 1,000 men and woman aged 20 to 85 who did not have heart disease or diabetes, those who consumed chocolate more frequently had a lower BMI than those who consumed it less often. On average, participants ate chocolate twice a week and exercised 3.6 times a week.
Health experts say a normal BMI is typically in the range of 18.5 to 24.9.
“People who ate chocolate more frequently consumed more calories, and they did not exercise more, but despite this they weighed less,” said Beatrice Golomb, with the university’s Department of Family and Preventive Medicine. “It’s not amount of chocolate, but frequency of chocolate consumption [that counts].”
“Chocolate has been linked to lower heart disease and more favourable liver profiles and better blood pressure,” Dr Golomb said. “The chief factor that has typically led people to hold back from recommending chocolate has been this concern that the expectation was that it would be associated with being heavier and gaining weight more, and this study at least does not provide support for that but rather the contrary.”
Consumption of certain types of chocolate has been found to have other metabolic benefits on blood pressure, insulin sensitivity and cholesterol level.
“Our study doesn’t really constrain exactly the amount of chocolate [people should eat], but it does suggest that more frequent chocolate consumption is associated with better BMI.”
But Professor Thomas said that the study showed “why association is not the same as causality.
“Paradoxes are not uncommon in medicine and usually reflect the influence of other unmeasured factors. The population studied also matters. In this instance, the impact of chocolate consumption on middle-aged overweight men may not reflect the harm confectionery does to women or adolescents.”
Professor Thomas said that the plant-derived flavanols found in cocoa products, such as dark chocolate, did have real effects on metabolism. However studies highlighting their health benefits invariably used very large doses “that could never be garnered by eating the amounts of chocolate described in this study. Most processed confectionery contains little of the original antioxidant potential of the original cocoa.”