What it means: Men who are heavier may be less resistant to bacterial infections, while their leaner counterparts could be more effective at staving off sickness. The reasons why aren’t entirely clear, but "men with lower BMIs might have stronger immune systems and therefore have better genes responsible for immunization," says study author Boguslaw Pawloski, PhD. Sometimes called the "good gene hypothesis," it’s one reason why men at healthy weights are seen as more attractive (from an evolutionary perspective, at least) compared to overweight or obese guys: They’re less likely to get sick.
The bottom line: Men with excess body fat aren’t just at risk for health problems like high cholesterol, hypertension, diabetes, and heart disease—they’re also more likely to have punier immune systems. "If the immune system is weakened, then opportunistic bacteria can cause serious diseases," says Dr. Pawlowski. In other words, consider this yet one more reason to keep excess pounds at bay.
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