I have met very few people who actually needed or wanted to gain weight.  Everybody from the obese to the ridiculously skinny seems to want to lose weight.  But the reality is that sometimes you need to gain weight for health reasons, and sometimes you don’t want that bony physique, especially if it’s getting to an extreme point where you cannot gain weight and it’s starting to worry you.  So how do you gain weight again?

1. Go to a doctor-chances are if you are having that much trouble gaining weight, you have one of two things: a medical condition or tape worms.  So it’s important just as it would be for your family pet to take a trip to the doctor and see if there’s anything wrong, especially including diabetes or a thyroid disorder.  These can be extremely dangerous to your health in general.
2. Start eating more fat-one of the best ways to gain weight is obviously to eat more fat!  That’s what my sister was told when she was younger and severely underweight, and unless you’re anorexic, which would explain severe weight loss, chances are you are not eating enough fat in your diet and therefore, it is a problem of malnutrition among other things.
3. Lift weights-this is an extremely healthy way to gain weight.  More muscle per square inch means less body fat, and it means more weight without actually suffering the related health problems of too much fat. 
4. Eat more-It’s simple.  But it creates more fat, and even if you are eating basically healthy foods, large masses of those foods will ultimately help you to gain more weight and it’s one of the best ways to gain weight.