An adult may be underweight for a number of reasons, including illness, stress, medication, or deliberate weight loss, but maintaining a healthy weight is essential in ensuring strong bones and the successful functioning of the body that's why To gain weight healthily, it's important not to simply fill your diet with junk foods because these contain saturated fats that induce sluggishness, build flabby body mass, and increase risk of coronary disease. This 7 days plan incorporates all the vitamins, minerals, and unsaturated "good" fats you need to gain weight in a healthy way.includes that 7 days meal plan for you.