In order to gain weight, you must plan your meals and exercise carefully (Shutterstock)

There are a number of people who struggle with being chronically underweight, despite having healthy appetites and no physical ailments.

In order to gain weight, you must plan your meals and exercise carefully:

 1.  Avoid falling into the trap of eating high-calorie processed foods eg pizza and chips as these have a negative impact on your heart health. It is best to focus on consuming high protein foods such as meats, fish, eggs and dairy products. These can include protein smoothies and shakes.

2. Snack on high density foods such as nuts and nut butters which will give you a calorie boost without leaving you too stuffed for meals.

3. Aim to eat more calories than you burn. This means you should monitor your calorie output when doing exercise.

4. Focus your workouts on strength training rather than steady state cardio to avoid burning too many calories.