If you’ve ever tried to lose weight by eating less and exercising more, you’re not alone. But what if that “eat less, move more” strategy is actually working against your goals? It sounds counterintuitive, but undereating can stall fat loss and even lead to muscle loss - and stress hormones like cortisol play a major role.

Here’s what’s really going on inside your body when you undereat - and why fueling your body properly is key to lasting fat loss and strong, lean muscle.

The Myth: “The Less I Eat, the More Fat I’ll Lose.”

At first, cutting calories might make the scale go down. But over time, your body gets the message that food is scarce and shifts into survival mode. In this state, your body becomes more focused on preserving energy than on building muscle or burning fat.

And here’s where things get tricky.

Enter Cortisol: Your Body’s Stress Hormone

When you don’t eat enough, especially over time, your body produces more cortisol, a hormone that helps you deal with stress. Cortisol itself isn’t bad - it helps regulate blood sugar and gives you energy when needed. But when it stays high due to constant under-fueling, it can cause problems.

High cortisol can lead to:

• Increased fat storage, especially around the belly

• Muscle breakdown (called catabolism)

• Cravings and binge eating later on

Basically, your body starts breaking down your hard-earned muscle to use as energy - while hanging onto fat. Not exactly the outcome you’re working so hard for.

Muscle Catabolism: When Your Body Eats Its Own Muscle

Your muscles need protein and energy (yes, calories!) to repair and grow. When you undereat, your body doesn’t have the fuel it needs, so it starts breaking down muscle tissue for energy.

This is called muscle catabolism, and it’s the opposite of what you want when trying to improve your shape or metabolism. Less muscle means a slower metabolism - which means fat loss gets even harder.

Why More Food (The Right Food) is the Answer

Fueling your body properly helps:

• Build and maintain muscle

• Lower cortisol

• Support a faster metabolism

• Burn fat more effectively

Instead of starving your body, think of food as a tool to help you train better, recover faster, and feel stronger.

The goal is to eat enough - especially protein and nutrient-dense meals - to support your workouts and daily energy needs. This doesn’t mean overeating or eating mindlessly, but rather giving your body what it needs to thrive, not just survive.

The Bottom Line

Undereating might feel like a shortcut to weight loss, but it often backfires - leading to fatigue, cravings, muscle loss, and stalled progress. The real path to a leaner, stronger body? Eat enough, train smart, and let your body work with you, not against you.

Need help finding the right balance? A personalized nutrition approach can take the guesswork out and help you fuel your goals without restriction or burnout.