That's it! With limited nutrients, no wonder the kid is gaining weight. People always praise the healthiness of mediterranean or eastern asian diet, but what they don't realize is that they eat a much diverse variety of food than Americans. Its not that they don't eat animal fat, but they eat everything, the fat, the inerts, the weird vegetables, but very little proceed food (although unfortunately this trend is changing due to an invasion by the American fast food industry). Equally important is how they eat. There's a Chinese saying "Eat a big breakfast, a nutritious lunch, and a small diner". The big breakfast replishes you after over 10 hours without food, the nutrious lunch keeps you going in the afternoon, and the small diner provide just enough calories until you go to sleep. If we compare that to American lifestyle, everything is just the opposite. In the morning we push for time, so many people just skip breakfast, during lunch we grab what we can to save time, and we stuff ourselves at diner as a reward for having a busy day.