The body’s metabolism is what converts calories into energy. Every time we eat our drink, our body uses those calories to fuel itself. Put simply, those calories combine with oxygen to create the energy the body needs to function. The faster our metabolism, the faster we burn calories. While many believe metabolism is to blame (or thank) for body weight, how many calories we eat and our level of physical activity have more of an impact. Though some experts say we don’t have much control over our metabolism, there are numerous studies that support the idea that some small changes (like drinking green tea, or amping up workout intensity) can increase the rate at which our bodies burn calories Metabolic effects of green tea and of phases of weight loss. Diepvens K, Kovacs EM, Vogels N, et al. Maastricht University, Department of Human Biology, Maastricht, The Netherlands. Physioloy and Behavior, 2006 Jan 30;87(1):185-91. Metabolic profile of high intensity intermittent exercises. Tabata I, Irisawa K, Kouzaki M, et al. Department of Physiology and Biomechanics, National Institute of Fitness and Sports, Kanoya City, Japan. Medicine and Science in Sports and Exercise, 1997 Mar;29(3):390-5. .