Ask the Dietitian: How Can Muscle Weigh More Than Fat?

Trinh Le, MPH, RD
by Trinh Le, MPH, RD
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Ask the Dietitian: How Can Muscle Weigh More Than Fat?

Chances are someone told you “muscle weighs more than fat” as an encouraging explanation for why you sometimes gain weight after adding strength training to a fitness routine. It’s also cited as a reason for why some people hit a weight-loss plateau. But a pound of muscle can’t weigh more than a pound of fat, so what’s the deal here?


It’s important to look at the saying “muscle weighs more than fat” in context. It’s not referring to weight, but rather, the difference in density between these two tissue types. Muscle is denser, weighing more per unit of volume compared to fat. Simply put: Muscle takes up less space than fat on any given body frame. This is why fitness enthusiasts like to improve their overall muscle-to-fat ratio rather than focus on their total body weight.


You can actually weigh the same and steadily be gaining body fat over time. Past age 30, muscle loss occurs at 3–5% per decade, accelerating to more than 15% per decade after age 50. Bone, another weighty tissue, also decreases in density due to aging. That’s why experts recommend strength training at least twice per week to help offset aging-related changes.


  1. It creates a leaner physique.
    Muscle is more compact and holds its shape better than fat.
  2. It boosts metabolism. 
    Muscle burns slightly more calories than fat and having more muscle mass is linked to lower insulin resistance since skeletal muscle can take in extra glucose when blood sugar levels are high.
  3. It improves mobility. 
    Muscle powers every activity you do, helping you achieve more physical feats.


Muscle is denser and may not show up favorably on the scale, but you should strive to preserve — and even build more — muscle as part of your weight-loss plan. Sadly, weight comes off as both fat and muscle. As rule of thumb, one quarter of your weight loss comes from lean (Read: muscle) tissue. You can shift this ratio in your favor by:

  1. Eating more protein. 
    The recommended daily allowance (RDA) for protein is 0.8 grams per kilogram of body weight, but you can benefit from going higher if you’re cutting calories for weight loss. Research recommends protein intake at 1.25 times the RDA for sedentary individuals and 1.5 times the RDA for active individuals.
  2. Exercising in addition to improving your diet. 
    You may know resistance training (aka: weightlifting) helps build and preserve muscle even as you lose weight. Endurance exercise counts, too. Two studies of middle-aged adults found brisk walking for about one hour daily helped preserve more lean muscle mass during weight loss compared to diet-only plans.
  3. Keeping an eye on your body-fat percentage. 
    It can be helpful to track progress quantitatively. Body-fat percentage indicates what percent of your total body weight is coming from fat. To get an idea of your number you can use a smart scale. It uses “bioelectrical impedance,” or a stream of electricity, to approximate body-fat percentage.


Don’t be discouraged if you’re putting in the hard work to eat better and exercise more but aren’t seeing much movement on the scale. Body weight paints an incomplete picture of your health and physique. Instead, focus on signs of progress that aren’t just a number on the scale such as how much energy you have, how much farther you can run and how well your clothes fit.

About the Author

Trinh Le, MPH, RD
Trinh Le, MPH, RD


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