Dr. Greger’s latest firestorm:
He makes a good point about prior cross-sectional studies being just a snapshot in time. Those studies found that eating chocolate was associated with lower weight. But … Maybe heavy people cut back on chocolate in an attempt to lose weight. If that was true, it would appear that heavy people eat less chocolate, and light people eat more. Indeed, that’s exactly what this prospective study found. The presumed weight benefits of eating chocolate went away when people with weight disorders were excluded:
Habitual Chocolate Consumption May Increase Body Weight In A Dose-Response Manner, PLOS One, 17 August 2013
More frequent chocolate consumption was associated with a significantly greater prospective weight gain over time, in a dose-response manner.
In this next study, an intervention trial (not a cross-sectional snapshot in time), adding 4 squares (25 grams) of chocolate to people’s daily diets caused them to gain 2 to 4 pounds in just 3 months:
Low Vs. Higher-Dose Dark Chocolate And Blood Pressure In Cardiovascular High-risk Patients, American Journal of Hypertension, June 2010
This was an interesting study, because even though they didn’t employ a no-chocolate control group, they did have a group that ate just a little chocolate – 6 grams or 1 square instead of 4 squares. Their end point was actually blood pressure, not weight. You know what? The 1-square eaters reduced their blood pressure more than the 4-square eaters, just shy of significance. Perhaps the weight gain offset the expected reduction in blood pressure?