2. “吃太多的高脂肪食品和不运动”是导致青少年 肥胖的主要原因；
参考词汇：肥胖 obesity；高脂肪食物 fatty food
A study has predicted that over 50 million children will be overweight in China by 2025 if anything isn't done.
A study has predicted that over 50 million children will be overweight in China by 2025 if anything isn't done. In China, the problem is becoming more and more serious because most overweight children like eating fatty food and they hardly exercise.
How should we solve the problem? Firstly, children must have healthy eating habits. They should eat more fruit and vegetables and less meat and junk food. Secondly, they should exercise often. It'll make them healthy and feel good. Finally, keep some good living habits such as getting up early and going to bed early.
In a word, healthy eating, proper exercise and good living habits can keep children from getting fatter.