You shouldn't its healthy. No!!!!! its not.
According to Harvard's Research it improves Sleep (apart from other benefits), hurray!
Only two quotes from the article to make sure you lose belly fat :) and improve your overall health.
1. Why losing belly fat improves sleep?
“So one possibility with the results of this study is that weight loss reduced sleep apnea and improved sleep quality,” says sleep expert Dr. Lawrence Epstein, an instructor in medicine at Harvard Medical School."
2. So, people who exercise will get better sleep?
"people who exercised at least 150 minutes a week slept better and felt more alert during the day than those who didn’t exercise much. (Don’t exercise right before bedtime, however. That can make it difficult to fall asleep.)"
If you want to find some tips go on read the Harvard University article on Losing weight and belly fat improves sleep (http://www.health.harvard.edu/blog/losing-weight-and-belly-fat-improves-sleep-201211145531)