Men who eat mostly processed foods may have sperm that don’t swim as well, which could make it harder to get a partner pregnant—even if they’re otherwise healthy.

Men who ate fewer carbs (especially sugar and white bread) had less damage to their sperm DNA, possibly because high sugar intake increases harmful stress in the body.

Eating mostly organic food may help protect sperm DNA and boost testosterone by reducing exposure to pesticides and increasing natural antioxidants.

Eating a lot of processed foods may lower two important hormones—one that helps control appetite and another that helps make sperm—which could hurt both your metabolism and fertility.