What are good drinks for during the day for someone who wants to gain weight and build up muscles? i don't mean supplements. ps. i'm doing exercises

Non-sugary drinks: If one is truly underweight (based on height, family background, and body type), a dr. Can evaluate. If no medical cause is found, then one can add weight by eating more calories of nutritious foods, while also doing weight-training to increase muscle. Proteins: egg white, chicken breast, salmon, ... Better fats: olive oil, peanuts, almonds, tofu, .... Easier to eat protein; not add it to a drink.