While chronological age is based on the number of years you lived—and you can’t really do anything to change that number—a few lifestyle tweaks may help to adjust your metabolic number. Here’s what to know about your metabolic age, how it affects your health, and methods for making your metabolism more efficient. However, to get an idea of your metabolic age right now, the most common formula is one called the Mifflin St. Jeor Equation (you can find a quick calculation here): Moday says you can also get a more specific BMR by using a bioimpedance machine, which features sensors that you put on your fingers and toe. It then sends an electric charge through your body, measuring your water volume, fat, and how much your bones contribute to your weight. “People with a higher muscle mass, because they have more metabolically active tissue, require more energy to keep going compared to those with more fat,” she explains. That’s why it’s more accurate to get a bioimpedance machine involved in calculating BMR rather than going off a formula that doesn’t take into account muscle and fat mass. Some studies do show a link between lower BMR and some health outcomes, including age-related mortality1 and diabetes. Also, metabolic age relates to your metabolic health, which is a strong indicator of overall well-being. Markers of metabolic health include things like waist circumference, blood sugar, triglyceride and cholesterol levels, and blood pressure (you can read more about that here). There is a downside to looking at BMR and metabolic age when it comes to your health, though—mainly, it’s nearly impossible to compare your personal BMR to others in your age group because so many factors play a role in how many calories you burn at rest, Moday says. Your body frame and shape, your ethnicity, your genetics can all play a role. Robin Forouton, RDN, a spokesperson for the Academy of Nutrition and Dietetics also says things like thyroid health, mitochondrial health, nutrient status, and metabolic flexibility (or how well your body transitions from a carbohydrate-burning metabolism to a fat/ketone-burning metabolism) can also play a role in BMR. In general, your goal should be to keep your BMR revving by living an overall healthy lifestyle. Moday recommends comparing your own personal numbers over time rather than equating your body (or BMR) to other people’s. “When you look at BMR, 70% is due to height and weight and genetics—that leaves about 30% of variables you can control,” she explains. In other words, certain lifestyle choices may positively affect metabolic age. Fitzgerald recently released a small pilot study with her team that found that following an eight-week program that included sleep, nutrition, and exercise components, along with relaxation techniques and supplements reduce participants’ biological age by three years—showing that while you can’t stop your chronological age, you can affect what’s happening internally. Fitzgerald says it’s also important to eat adequate protein to support lean muscle mass and avoid losing that tissue as we age. So make sure you’re getting enough of the muscle-building macronutrient for your body. Besides macronutrients, though, Foroutan recommends focusing on nutrient-dense foods. “Vitamins, minerals, amino acids, and other nutrients are critical to mitochondrial health, and mitochondrial health is instrumental in turning the food you eat into cellular energy,” she says. “Insufficient amounts of these nutrients can interfere with how efficiently your cells work, and that can lead to a sluggish metabolism. Iodine and selenium are also two nutrients your thyroid needs to work properly and keep your metabolism humming.” This healthy diet approach can also help to keep inflammation at bay and manage blood sugar—two more factors Fitzgerald says are important in promoting a younger metabolic age through food. In general, living an overall healthy lifestyle will help you reduce your metabolic age and support metabolism. As Fitzgerald puts it: “We cannot understate the importance of good diet, stress control, exercise, and anti-inflammatory habits.”
