YES it is true resveratrol increases metabolism and burns fat IN RODENTS! I´ve recently talked to an endocrinologist who conducted a randomized, placebo controlled clinical trial on obese men using high-dose (1500mg daily) resveratrol which found NO positive effects on metabolism or fatburning. So before you rush out to buy reveratrol and leucine you might want to do some critial reading of your own:
High-Dose Resveratrol Supplementation in Obese Men
An Investigator-Initiated, Randomized, Placebo-Controlled
Clinical Trial of Substrate Metabolism, Insulin Sensitivity,
and Body Composition, 2012, Diabetes, Clinical trial reg. no. NCT01150955