As we age our resting metabolism, the rate at which our body uses energy, does begin to slow down. When it comes to aging often times our eating habits also have to change because our metabolism change. While some say this is a bad change, there are others saying this is actually a good thing. When our resting metabolism slows down it actually slows the aging process and your energy is conserved. It does mean though that you will not need as many calories so if eating less as your age is difficult, so will be keeping the body fat off as well.
Some may say, “what if I love food and want to be able to enjoy as much as possible?” The only way to be able to do that would be to increase your resting metabolism, and that may be possible. There is a small change when you drink caffeine, eat more protein, drink more water, and eat more often. Although, the change may be so minimal that it wouldn’t really be changing your metabolism.
Your resting metabolism does change based off how large you are. The more weight you are the more energy it takes to just exist, so theoretically by increasing in size you will increase your metabolism. This isn’t the answer most people are looking for because they are more often then not trying to lose weight. So, if you are wanting to lose weight and give your resting metabolism its greatest opportunity for increasing, you must gain muscle. Muscle weighs roughly 3x more then fat and will require more energy to function then fat.
Overall, if you are wanting to increase your metabolism then your greatest opportunity for any real change will be in increasing your muscle mass.