The Muscle/Metabolism Link

A study published in the journal Science in August 2021 found that our metabolism does not change as much as we thought. Even after age 60 our metabolism only drops around 0.07% per year. We know, we know - it’s good news, but leaves you wondering why you’re having so much trouble with post-menopausal weight gain (and weight loss).

What does change, however, is our ability to make muscle from protein. A 20-something can turn 16 or so grams of protein into healthy new muscle cells in a process called protein synthesis. Older adults need at least 25 to 30 grams of protein at a time to kick start this muscle building process.

One missing piece of this puzzle - especially for women in perimenopause and beyond - is the role of hormones in muscle maintenance. Estrogen plays a quiet but important role in supporting muscle repair, insulin sensitivity, and fat distribution. As estrogen levels fluctuate and decline, the body can become less efficient at directing nutrients (including protein) into muscle tissue. Instead, more calories are stored as fat, particularly around the abdomen. Progesterone also matters. While often discussed for mood and sleep, progesterone supports recovery and helps counteract inflammation. When progesterone is low, recovery from workouts can feel harder, soreness lasts longer, and motivation to strength train can drop - all of which indirectly contribute to muscle loss over time.

Why Does Muscle Building Matter?

We constantly break down and rebuild muscle. When the destruction rate is greater than the rebuild rate, we end up losing muscle mass. Somewhere in our mid to late 30’s we begin losing muscle mass at a rate or 3-8% a year. Here is where age and weight gain connect.

The less muscle we have, the more fat we gain. Muscle burns calories faster than fat does AND it helps control blood sugar. The less muscle you have, the higher your blood sugar, and the more of that blood sugar is forced to convert to fat.

Muscle, Insulin, and “Stubborn” Weight

Muscle doesn’t just burn calories - it acts like a metabolic sponge for glucose (blood sugar). When muscle mass declines, insulin has fewer places to shuttle glucose, leading to higher circulating blood sugar and increased insulin release. Elevated insulin makes fat storage easier and fat loss harder, even when calorie intake hasn’t changed much.

This is why many women experience the very specific frustration of “doing all the right things” - eating well, exercising, cutting calories - yet seeing the scale barely move. Without enough muscle, the metabolic machinery simply isn’t as responsive.

Inflammation, Cortisol, and Muscle Breakdown

Chronic stress and elevated cortisol further complicate this picture. Cortisol is a catabolic hormone, meaning it breaks tissue down - including muscle. High or dysregulated cortisol can accelerate muscle loss, increase blood sugar, and promote fat storage, particularly in the midsection. This creates a loop where muscle loss drives metabolic dysfunction, which then makes rebuilding muscle even harder.

Supporting muscle, therefore, isn’t just about looks or weight, it’s about calming inflammation, stabilizing blood sugar, and protecting long-term metabolic health.

What Else Does Muscle Affect?

Muscle loss has also been linked to increased inflammation which increases the risk of diabetes, cancer, heart disease, Alzheimer’s and a compromised immune system. Yikes!

If you are thinking that it seems easier to gain fat as you get older - biochemistry is on your side, just maybe not in the way you thought. In addition to regular weight bearing exercise to build and maintain muscle, eating at least 25 grams of lean protein at each meal will support that muscle building process and help keep you in tip-top shape!