If you already have belly fats, you need to lose it with cardio exercise. From personal experience, I lose belly fats before by doing sit ups and push ups. I try to do 100 repetition five days a week. It measure my stomach first before starting it and I lose 1 kg over all weight after 2 weeks of being consistent. I also do 3000 steps a day because it can burn my calories as well. I do not sleep after eating. We get tired after eating because our stomach is full, but it needs for us not to take a nap because the digestion will happen. Some people advised to do planking. You start to do 20 seconds to one minute for a month and you could see the amazing results. I am not consistent with planking because it is way too hard for me so I might as well do the sit ups, push ups and squats, 100 repetition a day. Do not forget to drink more fluids. The more water, the more digestion works and toxins will all push away from our body.