Growing during adolescence and early adulthood requires more food energy than during other life stages. You may be underweight and having a tough time keeping up with the energy needs of your body. This could be because you are growing taller, exercising a lot, or you might simply have a fast metabolism (the way your body burns energy and calories).

Sometimes being underweight can be just as hard to handle as being overweight.

Here are some healthy ways to gain weight:

• Drink more milk - aim for up to three glasses of full-fat milk or fermented milk (amasi) a day.
• Choose nutrient-rich foods. These are foods like oats, millet, mealies, rice, porridge, bananas or wholegrain brown bread.
• Eat more good fats. Choose full fat fermented milk, nuts, fatty fish like pilchards or sardines, and peanut butter.
• Watch your drinks: Don't fill up on fizzy drinks, tea, coffee and other drinks. These have few calories and little nutritional value.
• Eat just before going to bed. Have a nutrient-rich snack like a peanut butter sandwich with a banana just before you go to bed.
• Avoid too many treats.. Even when you're underweight, be careful of too much sugar and fat.
• Get some exercise. Strength training can help you gain weight by building up your muscles. Exercise may also improve your appetite.

Being underweight can be a problem for your immune system. You may not be getting enough vitamins, minerals (such as iron and calcium), protein, or fat for a healthy body. When your immune system is weak, you are more vulnerable to germs and medical conditions.

A few simple changes can make a big difference to your health. When you’re getting the nutrition you need, you feel great and have lots of energy.