Increasing weight will require increasing your calorie intake, which basically means that you will have to start eating more food. Consuming more calories will cause your body to store the extra calories for later. These stored calories will start adding extra pounds to your body if you do not utilise them quickly enough. Even though you have a license to eat more, it does not mean you start helping yourself to an increased amount of junk food, processed food or food cooked in saturated fat as such foods are unhealthy. Go for foods that are healthy and have a high nutritional value as well.
Increase your daily intake of healthy fats by eating foods such as salmon, flax, tuna and walnuts. These foods contain omega-3 essential fatty acids, which are a rich source of energy. Your body will store any excess amount of these fats without comprising its healthy state.
Increase your protein intake by eating including foods such as fish, poultry, lean meats, legumes and seeds to your diet. Protein is utilised in building and repairing muscle. An increase in muscle mass will result in an increase in weight.
Increase the number of meals that you eat in a day. Make the meals smaller than the ones that you eat three time a day, as eating large meals will curb your appetite to an extent that you would not feeling like consuming food for a greater amount of time. Smaller meals will sate your hunger just enough to make you start feeling hungry in a couple of hours.
If you can get your hands on healthy snacks between meals, it would be of great help. Look for leftovers in the fridge. Once again, do not let the temptation of eating junk food get the better of you.
Doing resistance exercise such as weight training will help you build muscle mass. As explained before, muscle has the same effect on weight as fats, though the former is a much healthier addition than the latter. Be sure to keep yourself hydrated during your exercise session.