Our weight should be proportionate to our height. For every given height there is a normal weight range.
You must do several things correctly to gain weight.
A healthy diet: this is the foundation of gaining weight. If you don't do this right, the other things you do won't be effective and could even be harmful. Follow the following tips:-
• Pay attention to your health and food intake.
• To increase your appetite, have a glass of lime water or 1 cardamom (elaichi) before your meal.
• Have minimum 4 meals in a day.
• Drink 1 glass of milk twice a day.
• Try to enjoy your meals and gradually increase the quantity you eat every time.
• A balance diet should have all essential nutrients in it. Breakfast is the most important meal of the day. It should include combination of Both Carbohydrates and Proteins for e.g. Oats with Milk or Poha/ Upma with a glass of milk. If you do not like milk have 1-2 egg whites in the morning along with your breakfast.
• You need to focus on your protein intake : Increase your protein intake e.g. milk, dairy products- cheese, paneer, lentils (dals), nuts ( soya, peanuts, dry fruits ), pulses e.g. rajma, chole, kidney beans etc. sprouts. If you are a non-vegeterian, then you can have proteins by also eating eggs, chicken, fish. Make sure you are including at least 2 serving of any of these in your daily meal.
• Lunch and dinner again should be a combination of Proteins, Carbohydrates and Fats which could have dal, roti, sabji/chicken, salad.
• Please do have minimum 4 almonds or a small bowl of peanuts every day.
• Please ensure that you drink at least 3 litres of water every day.
Exercise: Some types of exercise are more effective for weight gain. If you are below 21 years of age, you are still in the process of growing and are just beginning training; you need to take a safe approach so please speak to a trainer for an appropriate regimen.
If you are above 21 years of age: assuming you don't have any medical conditions that would make it risky, you can do weight training to build muscle mass. There are different exercise regimens but the preferred ones focus on training large muscle groups (e.g. chest, back, thighs, and butt) and doing full-body exercises such as push-ups, squats, pull-ups, rows, etc.