Try to write down everything you eat for a whole day - don't change your eating habits, eat as you usually do - just write it down! Do that for three days. In the morning of day four, look at what you have written down! You will see that you are pretty much eating the same amount of food each day, without really having noticed it - that's what you have to change here on day four! An example: Lets say that you used to have a bowl of cornflakes with skimmed milk in the morning. All you have to do here, is to replace the skimmed milk with whole-milk! You still will be eating the same amount of food but in a different way - as whole-milk contains a lot more calories than skimmed milk! Another example: Lets say, at lunch time you used to eat a tuna sandwich and a bottle of water. Try this out: Put some salad oil in your tuna sandwich and drink a glass of orange juice instead of water! Again - you will still be eating the same amount of food, but again - just in another way! Get my point here?

The problem with people who are trying to put on weight, is the amount of food they have to consume - they simply cannot eat that much! The one and only way to overcome that problem, is to replace the food they are already eating with food with a much higher content of calories. But you can do even more than just changing your eating habits to improve your weight gain problems! Try to join a gym and lift some iron 2 - 3 times a week, this will build muscle mass and improve your body's ability to digest the food you are eating, which will also help you a lot to put on weight! Remember to drink a big glass of orange juice and eat a banana right after exercise to help the muscle building process!

Another vital factor is sleep! Try to get at least eight hours of sleep every night - and if you can, eat a peanut butter sandwich just before going to bed!

Try all the above for at least two weeks, and at the end of week two, you will have put on at least five pounds of body weight - not just fat but also some quality muscle mass as a result of the weight lifting routine as well!

NOTE: Before becoming involved in any kind of a diet or exercise regimes, you have to seek the advice of a health care professional.