In order to gain muscle, you need to do two things: stress your muscles with heavy weightlifting and resistance training, and consume enough calories to provide your body with the fuel it needs to get bigger and stronger.Do you think bodybuilding and vegetarianism are incompatible? Think again. From egg whites to legumes, many of the foods that make up the bulk of a vegetarian diet are rich in proteins, amino acids and calories that make muscle growth possible.Since meats like steak, chicken and pork are rich in calories, eating a caloric surplus is easy for omnivore bodybuilders. For vegetarians, it’s a little more challenging but still very much possible.Plenty of vegetarian foods are dense in calories and perfect for growth. Add natural peanut butter, which is packed with protein and healthy fats, to your meal plan for a quick and simple caloric boost.Other good options include beans, avocadoes and legumes. Remember that many of the most calorically dense vegetarian foods are high in fat and carbohydrates, so it’s generally best to use them as a ‘top up’ to your diet rather than its foundation.