Gaining those healthy pounds and muscle mass does not have to be a mystery anymore.

Whole grains contain high amounts of glucose or carbohydrates, which are energy giving foods. Whole grains are a healthy source of carbohydrates, which enable the protein to be used for increasing muscle mass rather than energy.

Nuts contain significant amounts of calories in a small serving. Two handfuls of almonds or around 18 cashew nuts can provide 160 calories.

This versatile fruit is rich in fat and calories. An average avocado contains around 300 calories and 31 grams of fat. Moreover, the fats contained in avocados are monounsaturated and hence, they are heart-healthy

Potatoes are one of the richest sources of carbohydrates and complex sugars. Therefore, they are highly recommended for underweight people.

They can be easily prepared in a variety of ways, and are considered as delicious, calorie-dense sources of carbohydrates. They are easily available and should be cooked with lots of greens or vegetables like spinach, broccoli, zucchini.