a 3.5-ounce serving of grilled chicken breast provides 165 calories, 3.8 grams of fat and 31 grams of protein. it's also a good source of iron, magnesium, potassium, zinc and b-vitamins. baked chicken breast, by comparison, boasts 151 calories, 3.1 grams of fat and 30.5 grams of protein per serving.