There are a lot of food products that you are encouraged to eat when you are malnourished. Aside from the usual fresh fruits and vegetables that generally everyone needs, you are also encouraged to eat more carbohydrates. Have a diet that is rich in rice, potatoes, and bread. You should also consider eating more protein. You can have more fish in your diet as well as lean meat.
You may want to add some beans to your food too. It will make a huge difference in how well your body will recover from malnutrition. It will also help if the reasons for becoming malnourished will be removed. You may also take supplements to improve your overall health.