Yes, beets. Studies have found that eating the carpet-staining veggie improves athletic performance.
Boiling spinach offers 6.43 mg of iron per 180 grams, more than a six-ounce hamburger.
One cup of sweet potato cubes has four times your RDA of vitamin A, which aids protein synthesis.
One form of this plant is the #1 source of vitamin D, which researchers believe may help develop muscle.
Red, yellow, or green—peppers have the most vitamin C, which burns fat and turns carbs into fuel.
If you want to grow muscle, eat soybeans as tofu or edamame.