My daughter is 13 and very overweight. I caused this by what we ate. If she is on genuine low carb (<35 carbs/day), avoiding grains and fruits, emphasizing meats and animal (or coconut/palm) fats, she loses weight. Anything else we have done, and those options have been many the last 3 years, she is miserable, obsessed with food, and gains weight. Bottom line: meat/amino acids are food, she is growing, she NEEDS the "building blocks of life." If she gets any less of them than she needs, she will want to eat or be unhealthy and unhappy. My rule to my daughter is this: eat all the meat and eggs you want. No limits. Eat all the lettuce, tomato, onion, pepper, salad you want -- but limit the ranch dressing. Take these vitamins. And we will eat together whenever possible, where we often add cheese or dairy in various forms to things. Lots of burgers with cheese (dipped in something like ranch), or taco plates, or scrambled eggs with veggies and cheese. She likes the food ok, and she is not hungry even though we recently shifted to eating only twice a day. If she is hungry I tell her to have coffee with cream, or meat, or eggs. This seems to be working for her. Fwiw.