Credit: Elizabeth Watt / Getty Images

Peanuts have ample amounts of protein and fiber – and that's about it. "They don't have cholesterol-lowering properties, and they're not high in vitamins," says Vogel.

When to grab a handful: Preworkout. "You're getting energy with little fat and fiber," says Upton. "Peanuts only have two grams of fiber and 14 grams of fat per serving."