Most detox teas contain caffeine, probably because this stimulant may suppress appetite, trigger your digestive system to let go of waste, and help you shed water weight. A caffeine-induced energy boost may also lead to working out a little longer or harder than usual. However, too much caffeine can also be risky (see above) and interfere with getting enough sleep–and catching too few zzzs may ultimately undo the tea's weight-loss effects. In fact, too little shuteye has been shown to trigger excessive eating and weight gain and even slow metabolism, which can make it easier to gain weight even if you don't eat extra calories. A good rule of thumb, regardless of where your caffeine is coming from, is to nix it at least six hours before bed. And if you're trying to shed pounds, commit to making adequate sleep a top priority.
The stress hormone cortisol can really screw with your belly. The problem with cortisol is two-fold: First, the chemical makeup of cortisol causes the body to store visceral fat. Visceral fat is stored between your main organs and in the midsection and is the most dangerous type of fat. Experts state that visceral fat increases the risk of diabetes and heart disease.