Many factors beyond muscle and fat can affect your metabolic age. That includes hormones and gender, Moday says. Our BMRs tend to be highest when we are young, while we are growing and developing, she says, but then it goes down in your 20s and continues to do so afterwards.
Some studies show a link between lower BMR and some health outcomes, including age-related mortality and diabetes. Metabolic age is also related to your metabolic health, which is a powerful indicator of overall wellbeing. Metabolic health markers include things like waist circumference, blood sugar, triglyceride and cholesterol levels, and blood pressure (more on that here).
However, there is a downside to looking at BMR and metabolic age in relation to your health – mainly, it is almost impossible to compare your personal BMR to others in your age range because so many factors play a role in the number of calories burned in peace, says Moday. Your physique 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, nutritional 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 that Play BMR.
In general, your goal should be to keep your BMR going through an overall healthy lifestyle. Moday recommends comparing your personal numbers over time rather than equating your body (or BMR) with anyone else's. "If you look at BMR, 70% is due to height, weight, and genetics – that's about 30% of the variables left to control," she explains. In other words: certain lifestyle habits can have a positive effect on metabolic age.
Fitzgerald and her team recently published a small pilot study that found that after an 8-week program that included a sleep, diet, and exercise component, as well as relaxation techniques and nutritional supplements, participants' biological age was reduced by three years. If you don't stop your chronological age, then you can influence the internal events.