For Metabolic Health Metrics, Body Composition Beats Weight

While weight is a broad biomarker that certainly contributes to an individual’s overall health, the number on your scale is rather nonspecific and, in fact, not the only measurement that matters when it comes to your metabolic rate and metabolic health. What’s more, it can be misleading. Weight is a gross estimate, not a nuanced metric. Body composition is multidimensional and personalized.

With that said, weight is an incredibly practical health indicator; and one of the most accessible in terms of measuring it ourselves and tracking changes over time. “After all, nobody has a dual-energy X-ray absorptiometry machine in their living room to measure their body composition. But a scale? Yes, that’s much more pragmatic,” explains mbg’s vice president of scientific affairs Ashley Jordan Ferira, Ph.D., RDN. “Clothing fit and an occasional waist circumference measurement with a tape measure are also contenders on the practical, track-it-yourself front,” she adds.

In its broadest sense, body composition components are muscle, fat, and bone. But you see, muscle is more dense and compact than fat. Meaning, muscle mass occupies less space than fat (aka adipose tissue) in the body. Therefore, someone gaining muscle could experience comparable weight gain as someone who’s increasing their fat percentage, so the difference lies in body composition. Likewise, weight loss could be a positive thing (if you’re making healthy, intentional lifestyle choices to lose fat, i.e., excess adipose stores) or a negative thing (if you’re unintentionally losing muscle, due to inactivity, inadequate protein intake, specific health issues, etc.). 

Vickery recommends her clients avoid the scale as a measure of success. “Weight can fluctuate for many reasons, such as hormones, water retention, and muscular growth,” she explains. 

Fellow dietitian, Ferira, concurs and divulges, “I don’t even own a scale! To each their own, but I just pay more attention to clothing fit instead of a number on a scale that appears more exacting than it really is.” 

And for individuals with disordered eating history or concerns, “a scale might be downright contraindicated and deleterious,” Ferira expounds.

Other measurements—like body mass index (BMI), which calculates an individual’s weight and height to roughly estimate if they’re in a generally healthy weight category (versus underweight or overweight)—are extremely helpful for health care practitioners, epidemiology researchers, and public health officials on the grand scale (i.e., for population studies, public health guidelines, etc.), but they don’t consider the highly unique and multifactorial nature of an individual’s weight. 

At mbg, we prefer to get personal and celebrate the unique individual. That includes considering body composition (i.e., the personalized matrix of fat, bone, and muscle that make up a human body) to be a more nuanced and useful metric when evaluating an individual’s metabolism and metabolic health.