Why Your Metabolism Slows Down — and How to Measure It with a DEXA Scan

Struggling to lose fat even though you’re eating less and exercising more? You’re not alone. As we age—or put our bodies through extreme diets and stress—our metabolism can slow down.

But the real question is: why is it slowing down, and how can you measure what’s actually happening?

Most people focus on calories and the number on the scale. But to truly understand your metabolism, you need a deeper look inside your body—and that’s exactly what a DEXA scan provides.

Here’s why your metabolism might be slowing down—and how a DEXA scan gives you the data you need to speed it back up.

What Is Your Metabolism, Really?

Your metabolism is the total amount of energy your body uses to function. It includes:

• Basal Metabolic Rate (BMR): Calories burned at rest
• Thermic Effect of Food: Energy used to digest food
• Physical Activity: Exercise and movement
• NEAT (Non-Exercise Activity Thermogenesis): Fidgeting, walking, standing

Key Fact: Your lean muscle mass is the single biggest driver of your metabolism. More muscle = more calories burned at rest.

Why Your Metabolism Slows Down

1. Loss of Lean Muscle Mass

Muscle burns 3–5x more calories than fat at rest. When you lose muscle—through aging, crash diets, or lack of resistance training—your metabolism slows down significantly.

2. Extreme Dieting or Chronic Calorie Deficits

Severely restricting calories can:

• Lower your metabolic rate
• Trigger muscle breakdown
• Lead to long-term fat regain

3. Increased Visceral Fat

Visceral fat (fat around your organs):

• Increases inflammation
• Disrupts hormone function
• Contributes to insulin resistance and slower metabolism

4. Aging and Hormonal Changes

After age 30, you lose 3–8% of muscle mass per decade unless you actively train. This age-related muscle loss (sarcopenia) slows down metabolism and increases fat gain.

How a DEXA Scan Measures Metabolic Health

A DEXA scan provides the most accurate body composition data, allowing you to understand what’s driving changes in your metabolism.

What You’ll Learn from Your DEXA Scan:

• Lean Muscle Mass (total and by region)
• Body Fat % and total fat mass
• Visceral Fat (measured in grams)
• Bone Mineral Density

These metrics reveal why your metabolism is slowing—and help you target the exact issue.

What to Do If Your DEXA Scan Shows a Slowing Metabolism

If You’ve Lost Muscle:

• Strength train 3–4x/week (compound lifts + progressive overload)
• Eat at least 1g of protein per pound of body weight
• Consider a slight caloric surplus to support muscle gain

If You’ve Gained Visceral Fat:

• Do Zone 2 cardio (40–60 minutes at 60–70% HR max) 2–3x/week
• Eat high-fiber, whole-food meals
• Reduce alcohol, sugar, and ultra-processed foods
• Improve stress management and sleep quality

If Your Bone Density Is Low:

• Incorporate resistance training and impact-based movements (e.g., jumping, plyometrics)
• Ensure proper calcium and vitamin D intake

How Often Should You Re-Test with a DEXA Scan?

For best results, re-scan every 4-8 weeks to track:

• Muscle gain
• Fat loss
• Visceral fat reduction
• Bone health improvements

Unlike the bathroom scale, a DEXA scan shows how your body is actually changing—so you can course-correct before hitting a plateau.

Book Your DEXA Scan in San Francisco at KALOS Today

Don’t let a slow metabolism hold you back. At KALOS, we offer expert DEXA scans in San Francisco to help you measure the key drivers of your metabolic health—so you can build muscle, burn fat, and optimize your energy with precision.

Schedule your scan today at KALOS—your journey to data-driven fitness starts now.

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