Why is my diet not working?

I don't know your stats and can't see your food diary but I would guess it's because you're starving yourself. Why would you want a negative net? You work out.....eat more! Your body needs fuel.

Also you're 15 and still growing, so please eat more. No need to diet now, just eat and stay active and don't even worry about calories. enjoy life!

Quoted for truth.

Don't use MyFitnessPal as a vehicle to starve yourself. Having a negative net is not the route to long-term, successful weight loss. You may lose for awhile, but once you start eating again, you will gain it back and then some. If you DON'T start eating again, then you'll be dealing with muscle loss, a reduction in bone density, hair loss, memory loss, mood swings, emotional problems, tooth decay, and possibly death.

Don't go this route. It's just not cool.

Instead, it's likely you don't have much to lose, so you need to have a very small calorie deficit, no more than 250 calories less than what you used to eat before this diet. So cut very little. Successful weight loss with teens usually means eating smaller portions, cutting out some sweets like pop, etc. And while starvation dieting is the fad with teenager girls (and a lot of adult women, too, I hate to say), it's royally stupid.

Sweetie, please, please make sure you are eating enough. I used this site http://www.bmi-calculator.net/bmr-calculator/ to check based on your stats and it looks like your BMR (the base amount of calories your body needs just to survive, even if you were laying in bed all day) is 1500. Assuming you're moderately active, you would need about 2300 calories a day to maintain your current weight.

You are clearly not overweight, so even if you want to shed a few pound it should be done moderately and sensibly. I would aim for eating midway between your BMR and maintenance calories (1800-1900 calories a day). That alone will give you a 400-500 calorie deficit per day....enough to lose about 1lb per week. And if you exercise a lot you need to up your eating on those days as well.

I have been where you are.....not too heavy but very much wanting to be thinner. I have tried eating low calorie. It does not work - maybe very short-term. You are still growing - you need to nourish your body with good foods, protein and healthy fats. Do not be afraid of food - use it as a tool to get where you want to be.

Help, I am staying under my 1200 calorie goal and have done for about a week now and today I even had a negative net because I burned more calories than I ate.. so why aren't I loosing any weight!?!

Also you're 15 and still growing, so please eat more. No need to diet now, just eat and stay active and don't even worry about calories. enjoy life!

Yikes. Yes. Your BMI falls in the healthy range, you're young and you're growing. Please forget the diet and just exercise. If you must, focus on eating 'healthy' but do not calorie restrict.

If you eat too little your body with go into 'emergency' mode and will store every single calorie it can get! You need to eat!

Please think about this. When I was your age I was anorexic, and like you, starved myself. I know now that it was the worst thing I could do for my weight. When you don't get enough to eat your body's metabolism gets messed up, Now, here I am, 26 and over weight. I think a great part of that was from my teenage years of not eating and now my metabolism is all screwy.

If you want to lose weight/maintain your weight it's truly simple at your age. Get lots of exercise and eat healthy. And NO, for the rest of us, don't give up eating pizza, ice cream, candy, cake, etc. Just eat a normal-smallish portion. Don't deprive yourself of what you love!

Only a week? Give it some time. Myfitnesspal recommends that you NOT weigh yourself daily because weight fluctuates so much. They recommend weekly weigh-ins. Just keep doing the right things and give it some time.