Your Metabolism controls the amount of calories you burn throughout the day and therefore determines how fat or thin you are. Although your metabolism slows with age, it’s quite simple to turn back the time by speeding up your metabolic rate, effectively slowing down the aging process! Your metabolic rate is the speed at which you burn calories. On average, 65-75% of this is accounted for by your resting metabolic rate (RMR). This is the calories you burn doing nothing at all, just running your body. Your RMR is determined by your age, weight and the amount of muscle you have. Building muscle mass is the only way you can increase your resting metabolic rate, and you have to train with weights to build muscle. (And for the ladies, this doesn’t mean gaining bulky muscle. It simply means toning up). You’ll need to train intensely with weights for about 20 minutes, 3 times per week for best effect. You can also get good effect by doing intense cardio training. Don’t go beyond 20 minutes but do high-intensity interval training (HIIT). E.g., after warm up and stretch, do 1 minute fast / one minute recovery and keep repeating for 20 minutes. Numerous studies show that this burns more calories (both during and after your session) than a steady session.