Even better than preventing muscle loss is building new muscle. Not only will this have an immediate positive effect on the appearance of your body (and you’ll be stronger!), you’ll also burn more Calories all day - even while you sleep. Wondering how much? Well, believe it or not, researchers don’t all agree on the exact amount. But it’s somewhere around 5-6 Calories per day per pound of muscle. By comparison, each pound of fat burns around 2 Calories per day. For one piece of research on this, see The underappreciated role of muscle in health and disease by Robert R Wolfe. As with preventing muscle loss, the type of exercise you’ll want to perform to build muscle is weightlifting (or other resistance training). As with everything else in this field, nobody agrees on the best way to lift weights, so you’ll have to do your own research and come to your own conclusions. As a general rule, I recommend 4-7 exercises involving the major muscle groups in a workout lasting around 20 minutes.