Go To Sleep!
Even Just getting an adequate amount of sleep will help you keep belly fat off. Without proper sleep your body tends to shut down during the day, so bye,bye workout because you tell yourself your too tired to workout. Also, your hunger level shoots way up...so much for the reduced calorie intake for the day, no sleep makes your body way more hungry. Studies prove it.
ZZzzzzzz

Men's Health Study on Sleep and Weight loss Click