Should you do sport on an empty stomach to lose more weight? Not sure. "At the time, we burn 30% more fat. But studies show that there is a rebalancing during the day. In the end, the body will not consume more calories", Active Lean Keto, a specialist in chronobiology and nutrition at the National Institute of Sport, Expertise and Performance . 

https://goketoganic.com/active-lean-keto/