How to gain weight in a healthy way?!

Best Answer - Chosen by Voters

Build muscle

Recommended Ways to Gain Weight

Have meals with the right balance of proteins, carbohydrates, and the right kinds of fat (such as unsaturated and monounsaturated fats, olive oil, canola oil, pistachios, almonds and walnuts). Heinemann suggests the following ratio: 60%-70% carbohydrates, 10%-15% protein, and a small amount of fat.
Eat foods higher in calories, vitamins, and minerals, as opposed to higher in fat or sugar.
Pack more nutritious calories in each serving. For example, you may add grated cooked eggs to mashed potatoes, ground chicken to soups and gravies, cheese in casseroles, eggs, and soups, and nonfat dried milk in soups, shakes, milk, and mashed potatoes.
If you get too full too fast, try having more high-calorie foods or slices of foods as opposed to consuming the whole thing (raisins versus grapes, granola and Grape Nuts versus corn flakes, mango slices versus the whole mango).
Limit drinking beverages to a half-hour before and after a meal.
Drink mixed juices (apple/berry, peach/orange/banana as opposed to one juice beverages) for a higher calorie intake.
With moderation, you may add in good fat sources to meals such as nuts, avocado, olives, and fatty fish (salmon and mackerel).
Snack in between meals. Nuts, dried fruits, and yogurt are good options, but it's also important to find nutritious foods that you will enjoy.
Have a nutritious snack before bedtime, such as a peanut butter sandwich.

good luck! and I'm not sure if they say it in the list, but as you age you will gain weight. Everyone does.

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Take whey protein isolates, eat more fatty fish, and proteins like chicken. Thats the best advice that i have.