If he workout everyday you should give him some snacks or a bit more food. If not, he's gonna feel sluggish and weak for burning off all that energy. Just because you want him to lose weight doesn't mean that he can't eat. Just pick him more healthy choices. He is growing so if you want him to be at his max potential let him eat but make sure it's healthy. It's also okay to splurge on unhealthy food once in a while. We are only human after all.