ROBERT SIEGEL, HOST:
From NPR News, this is ALL THINGS CONSIDERED. I'm Robert Siegel.
MELISSA BLOCK, HOST:
And I'm Melissa Block. Here's one from the run-that-by-me-again department. Chocolate may help make you thinner. See what I mean? NPR's Allison Aubrey has details on a new study. It suggests those of us with a chocolate habit could be doing our body weight a favor.
ALLISON AUBREY, BYLINE: Physician Beatrice Golomb says prior research has hinted that chocolate may favorably influence metabolism and she was curious to find out whether this would be reflected in chocolate lovers' body weights.
BEATRICE GOLOMB: Well, you know, I actually had the hubris to think that the metabolic effect might be such that modest amounts of chocolate eaten regularly could be body mass index neutral.
AUBREY: Meaning, perhaps all or some of those calories could be offset by the way our bodies handle chocolate. To test this theory, Golomb and her colleagues asked about 1,000 men and women aged 20 to 85 years old to complete a food frequency questionnaire, or FFQ.
GOLOMB: The FFQ asks in depth questions about regular foods that people have eaten recently and calculate things like calories consumed.
AUBREY: From people's answers, they determined how much chocolate people consumed and how often and then she and her colleagues recorded each person's BMI, or body mass index. And what did they find?
GOLOMB: In our study, people who ate chocolate more often actually ate more calories, but in spite of that, they had lower body mass index.
AUBREY: How much lower? Golomb says, if you take a five foot tall woman who weighs 120 pounds, this study found that, if she was a regular chocolate eater, she was likely to be about five pounds lighter compared to someone who didn't eat much chocolate. And it's not because she was out running marathons.
GOLOMB: In fact, people who ate chocolate more often did not exercise any more, so exercise was not an explanation for the finding.
AUBREY: Now, none of this proves that chocolate can help people maintain healthy weights and the researchers didn't suss out whether the type of chocolate made a difference, but they did find that the correlation to thinness started to melt away among the people who had the highest consumption. And this suggests that there is a point at which the metabolic benefits don't cancel out the extra calories.
Even so, Golomb says her findings still support the idea that the body doesn't treat all calories the same way.
GOLOMB: I think a really important point is that it isn't just the number of calories that matters, but the composition of calories.
AUBREY: Not all researchers are convinced of this. Broadly speaking, the calories in, calories out method of managing weight is effective for most people. But what research is showing is that certain foods contain compounds that have some power to influence metabolic factors in a favorable way and chocolate is one of them, explains food scientist Joshua Lambert of Penn State.
JOSHUA LAMBERT: When people talk about the health beneficial effects of chocolate, they talk about these compounds called polyphenols.
AUBREY: Now, polyphenols may have a range of beneficial biological effects, but Lambert says he focused in on one possible mechanism that could help explain the new study.
LAMBERT: When we started looking in our lab at some of these compounds in cocoa, these polyphenolic compounds, we actually found that they very potently inhibited the enzyme that's responsible for digesting dietary fats.
AUBREY: This means that the fat that comes with chocolate may exit our bodies before it has a chance to be absorbed. In other words, these compounds in cocoa could help us fend off fat?
LAMBERT: Right. You don't absorb the fat.
AUBREY: Now, Lambert says the caution here is that his lab work has been done in test tubes and mice, not people, like the U.C. San Diego study.
LAMBERT: There's a big leap from what we're doing to what they're doing.
AUBREY: But it could be one explanation that explains why frequent chocolate eaters tend to be leaner. Whatever the explanation, Beatrice Golomb says this is the thought she'd leave chocolate lovers with.
GOLOMB: Maybe those of us who do eat chocolate a few times a week can feel less guilt.
AUBREY: And be reassured for now that a little chocolate may, in fact, be good for your waistline. Allison Aubrey, NPR News.