Wellness Health & Well-being What Is Metabolism and How Do You Change It? By Mary Jo DiLonardo Senior Writer University of Cincinnati Mary Jo DiLonardo covers a wide range of topics focused on nature, health, science, and anything that helps make the world a better place. our editorial process Mary Jo DiLonardo Updated April 02, 2019 Your metabolism is affected by your body size, gender and age. Kotin/Shutterstock Share Twitter Pinterest Email Wellness Health & Well-being Clean Beauty If you gain weight easily or just can't seem to lose it when you want to, you might blame a slow metabolism. Maybe you know someone who can eat whatever she wants, and you curse her for having been blessed with a fast metabolism. But do you really know what metabolism is and how much it really has to do with weight gain and loss? Before you give metabolism all the blame (or credit) for something, here's the lowdown on this important, yet somewhat misunderstood bodily process. What exactly is metabolism? Metabolism refers to the biochemical process in which your body converts everything you eat and drink into the energy it needs to function. The calories in food and beverages are mixed with oxygen to release that energy. But the process doesn't just happen when you're working out or otherwise exerting yourself, points out the Mayo Clinic. Even when it seems like you're doing very little, your body still needs energy for breathing, repairing cells and circulating blood. How many calories your body uses for these basic functions is your basal metabolic rate — or what you think of as your metabolism. What determines your metabolism? Men usually burn more calories than women because they have more muscle and less fat. Syda Productions/Shutterstock People who are roughly the same size can have completely differently metabolisms. One person can eat whatever, whenever he wants and not gain weight while the other has to watch every bite. "We don't understand the mechanism that controls a person’s metabolism," Will Wong, a researcher and professor at the Johns Hopkins Center for Metabolism and Obesity Research, tells Vox. Some characteristics typically seem to determine the speed of someone's metabolism, according to Mayo, including: Body size and composition: People who are larger or who have more muscle mass burn more calories, even when they are resting.Gender: Men usually burn more calories because they typically have less body fat and more muscle than women of the same age and weight.Age: Your muscle mass tends to decrease as you get older and fat makes up more of your weight, which slows down how quickly you burn calories. Can you change your metabolism? Fresh and dried chili peppers were the most frequently used spice in dishes. Adam Baker/Flickr You can't change your age or sex, but there are ways you can try to give your metabolism a boost, says WebMD. Some things to try: Build more muscle. It's a small difference, but people with more muscle burn more calories because muscle uses more energy than fat at rest. Be more active. Getting more aerobic activity steps up your metabolic rate even after you've finished exercising. Don't skip meals. Eating too little or not often enough can slow down your metabolism. Eat a small meal or healthy snack every three or four hours. Get spicy. Using chili pepper and other spices can temporarily speed up your metabolism a little. Drink coffee and green tea. Both beverages give you a short rise in metabolism and offer caffeine, which can perk you up and let you exercise longer. Rest up. When you don't get enough sleep, your body can make too much insulin and that can trigger the body to store too much fat, according to the Rush University School of Medicine. So, there are some things you can do to speed up your metabolism, which may help with weight loss. But if you want to drop a few pounds, the formula is simpler. Says Harvard Health: "The reality is that for most people, excess weight is not all due to bad luck, thyroid trouble or some other unexplained, uncontrollable external factor. It's simple accounting involving calories in and calories out that determines changes in weight over a lifetime."