Okay i know a lot of people don’t have a problem with gaining weight but i do. I can’t gain weight no matter what i do. I am 15,5`1 and only 88lb…
WHAT SHOULD I DO?
Moving to General Questions.
See a doctor.
Really…what could we possibly suggest? If you eat over 1200 calories a day, you should be gaining weight. If not, you COULD have a problem absorbing nutrients/fat/protein and only a doctor could look into that. Various conditions can be at play. Some harmless, some not.
Could be anything from thyroid problems to crohns disease to just a poor diet in which you overestimate your calories and live and very active lifestyle due to sports or something.
kb9006, you must be my sibling. No answers, just sympathy.
Without seeing your diet, I have no opinion. Also, M/F ? Activity level. Siblings the same? Parents thin?
Grow.
No, really. I was your size and weight at that age. I was up to 6’ and 125 by 18, and I’m still 6’ now but I’m 155 lbs. or so.
Be patient, grasshoppah, and the chubbiness will come.
Yep, at 15 I was your size. I’m 27 now. 5’6" and 135lbs. Don’t be worried about your weight. Especially at 15.
Lift weights.
You will put on muscle weight, which is the right kind of weight.
It will also make you look better.
Since the OP is seeking opinions, this might be better served in IMHO.
kb9006, please use descriptive titles when starting threads. I have edited this one to indicate the subject.
Colibri
General Questions Moderator
At 15, I wouldn’t worry about it. When I got my license at 19 I weighed 98lbs (5’5"). If you’re really worried, talk to a doctor.
I assure you, you might feel underweight because you’re used to seeing bustier, hippier, chunkier people, but you’re probably still in a healthy range. Look at pictures and statistics of people in other countries. It made me feel more normal.
Up until this year, I was having the same problems. I’d eat like a horse and still only weighed 120lbs at 5’10".
My solution? I started eating TWICE as much as before. I literally order double the amount of food I used to, and I’ve gained 16lbs since December. I have no idea if this is healthy, though 
1200 calories a day for a growing teenager? That seems low.
If the OP hasn’t gotten this checked out by a doctor, he/she should. If there’s a medical problem any diet advice could do more harm than good.
Are you a girl or a guy? If you’re a girl, try a sport for muscles and curves and eat healthy. But accept that you’ll probably always be very slender and petite, it’s your body type.
If you’re a boy (my bet), just wait. You probably haven’t hit your growth spurt yet. Some boys start later. Weightlifting and protein would help you put on some muscle in the meantime and give you a good base for when you do start growing. If you never grow, take up gymnastics, it’s ideal for shorter guys and will help you grow strength. Plus gymnast boys are always hot.
Lift and eat even if you are a girl. I posted this link in another thread and it was followed with this link for plenty of follow up information and examples of how to lift. You can’t gain if don’t eat and if you don’t lift you’ll only get fat.
Not sure about your exact situation but I had a friend in high school who over the course of a week ate two Jack-in-the-box bacon ultimate cheeseburgers a large Oreo cookie shake and a large order of curly fries three meals a day he put on about 30# in that week. Not sure why you would want to do that but that’ll do it no matter what your activity level is.
Exercise and eat well.
I ate a lot as a teen, particularly during sports season. Athletes often eat a greater number of smaller meals, about every 3 or 4 hours and up to 6 times a day or more, in preference to eating only three larger meals. One project in freshman biology was to track your diet for two weeks. I was taking in over 3000 calories during swim season, and had body fat that was no higher than the low teens. Yes, I was actually burning through that much food; my sisters teased me by calling me the human garbage disposal, because I’d finish stuff that was left on everybody else’s plate when they were done. I could usually tell when I was going through a growth phase because I’d be constantly hungry, even after eating a big meal.
Low-fat and vegetarian diets will not help you grow as much as a healthy (note the qualification) omnivore diet with lots of protein and decent levels of fat. A split of 40/40/20 or 30/40/30 of protein/carbohydrates/fat is probably ideal. See The Zone diet for a more detailed view of how that kind of eating plan works.
Your total daily calories should reflect the idea that you’re looking to add mass. Most calorie recommendations are made for adults who are trying to either lose weight or do no more than maintain their current weight. You’re going to want to pad the calorie count a bit, about 10–15% — unless the recommendation has already taken both your age and sex into account in the calculation.
Don’t think you’re going to be small forever. I was way smaller than everyone else until about age 13, when I went through one major growth spurt that brought me up to almost average. I did gymnastics from 10 until I was about 14 (quit from lack of time) and that made me strong as hell for my size. Even so, I was only about 5’3" and maybe 100 lbs. at 14. I never had another big change in height, just grew steadily. I’m 5’10 and 175 lbs. now.
To Gut’s links, I’ll add one to the workout program I’m doing now: Crossfit. They have a site that gives info for younger athletes: Crossfit Kids, which is probably more appropriate for your age and size right now. See if there’s an affiliate gym in your area. Crossfit will turn you into an all-around athlete, who has tons of strength and power coupled with good endurance. Plus, you’ll be ripped and lean, which is always a good look.