Dairy Products
Fermented dairy products like plain yogurt and kefir contain probiotics or good bacteria that keep the digestive tract in good working condition to take in the maximum amount of nutrients and calories from the meals you eat.
Whey protein is a convenient and quick source of inexpensive protein that is used extensively by bodybuilders. If you’re not looking to gain that much muscle mass, adding whey protein to your smoothie or shake for a post-workout drink is adequate.