Please read this. I used to weigh about 200 lbs at 5'3" and trust me, I feel so much better now that I have lost 60 or so pounds. When you're overweight you just feel bad all of the time. You're slower than everyone, it's difficult to breathe, you're tired all of the time, and it also has connections with depression. Arthritis, joint problems, back problems, higher risk of cancer, so on and so forth.... Remember, all that extra fat is going to be pressing up against organs and nerves and it's going to be very uncomfortable and can cause sciatica, which is very painful. It seriously weakens your immune system so you're sick much more often. It's a serious risk to your health. Considering the fact that you are planning on nearly doubling your own body weight, not to mention 240 lbs on a 5'6" skeleton is considered borderline morbidly obese at 38.7 on the BMI scale (40 being morbidly obese) you're going to really mess yourself up. You're still young, don't throw a healthy body in the trash before you no longer have a choice. It's the only one you've got.
128 lbs for your height is right in the middle of the "normal" weight range at 20.7 . Please, don't gain weight just because you want to look like your favorite celebrity. You have a life still far ahead of you; don't ruin the vessel you carry it in before you're 30. If you're serious about gaining some extra fluff, I recommend you gain no more than 30 lbs, and do it healthily using foods that are not processed but rather natural oils and nuts while still eating all of your daily servings of fruits and vegetables. Fruit juices tend to have a lot of calories; try the "Naked," or "Odwalla" brand.
I wish you health, luck, and happiness.
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I am the wise little owl in the linden trees near the water.