The Truth About Lean Muscle, GLP-1s & Women’s Metabolism

For years, endocrinologist Ana María Kausel, M.D., devoted her career to helping patients restore hormonal balance and rebuild their health. But when she experienced her own health begin to shift, she realized just how misunderstood women’s metabolism truly is—and how much of the conventional advice around diet and exercise gets it wrong.

“I wasn’t working to fit into a dress,” Kausel says. “I was working to improve my metabolism and my body composition—to feel strong again.”

Hormones play a major role in how your body burns energy, stores fat, and builds muscle. But according to Kausel, the real key to a resilient metabolism lies in what’s happening inside your muscle tissue.

“When you train with weights, your muscle becomes the metabolic organ,” she explains. “It’s what determines how efficiently your body uses energy.”

As women age, muscle mass naturally declines—a process called sarcopenia that can begin as early as our 30s. The less muscle you have, the fewer calories your body burns at rest, and the harder it becomes to regulate blood sugar, maintain strength, and feel energized. 

Resistance training directly counteracts that process. Lifting weights helps preserve and build lean muscle mass, which in turn boosts resting metabolic rate, enhances insulin sensitivity, and supports long-term cardiovascular and hormonal health. 

Despite what diet culture suggests, Kausel emphasizes that cutting carbs or under-eating can backfire, especially if your goal is to build muscle and improve metabolism.

“If you really want to be strong and you want to do strength training, you need to eat carbohydrates,” she says. Carbs fuel your workouts and replenish glycogen stores in your muscles, allowing them to grow and recover. 

Pairing that with adequate protein (spread consistently throughout the day) provides the amino acids needed for repair and growth. Without enough of either, your body simply can’t build or maintain lean mass. That’s why Kausel encourages women to think less about cutting and more about fueling.

For optimal muscle health, she recommends aiming for high-quality protein with every meal paired with complex carbohydrates to keep blood sugar stable and provide steady energy for your workouts and recovery.

As a baseline, she suggests at least 100 grams of protein per day, though a more personalized target is 0.72 to 1 gram of protein per pound of body weight daily.

You’ve probably heard of GLP-1 receptor agonists, medications that help regulate appetite and blood sugar. While they can be incredibly effective tools, Kausel stresses that they’re not a substitute for metabolic health fundamentals.

These medications work best when combined with healthy habits—resistance training, nutrient-dense eating, quality sleep, and mental engagement. Together, these factors enhance the medication’s effects and protect against muscle loss, one of the most common side effects of rapid weight loss.

The future of women’s metabolic health isn’t about restriction, discipline, or chasing smaller. It’s about building—muscle, strength, confidence, and metabolic flexibility.