Weekly Live Recap: Metabolism 101 — What Actually Affects It and What You Can Do About It

Metabolism isn't one thing

When most people talk about metabolism, they're usually thinking about how many calories they burn at rest. That's part of the picture, but it's not the whole picture. Metabolism refers to the total energy your body uses across four main "buckets":

• Resting Metabolic Rate (RMR): The energy your body uses just to keep you alive — breathing, circulation, temperature regulation, organ function. This is usually the largest portion of your daily energy expenditure. Fun fact: your brain makes up about 2% of your body weight but uses about 20% of your resting energy.
• Thermic Effect of Food (TEF): The energy it takes to digest, absorb, and process the food you eat. For most mixed diets, this accounts for about 5–15% of daily energy expenditure. Protein has the highest thermic effect, which is one reason it's so helpful during weight loss.
• Exercise Activity (EAT): Your planned workouts — the movement that's intentional and structured.
• NEAT (Non-Exercise Activity Thermogenesis): All the movement you do outside of formal exercise — walking, standing, chores, errands, fidgeting. This is often the most overlooked bucket, but for many people it accounts for more daily energy than their workouts do, because it's happening 12–14 hours a day.

Why metabolism changes during weight loss

As your body weight decreases, your energy needs naturally decrease too. A smaller body simply requires less energy to maintain. That means the calorie deficit that worked early on may not produce the same results over time — even if your habits haven't changed.

On top of that, your body can adapt in ways designed to protect you. Megan compares it to watching your bank account drop: you'd naturally start adjusting your spending to protect your future. Your body does something similar. When energy intake stays low for a while, it becomes more conservative — slightly lowering resting energy, reducing the drive to move, increasing hunger and cravings, and becoming more efficient during exercise.

This is metabolic adaptation. It's not damage, and it's not permanent. It's your body doing exactly what it's designed to do.

The most overlooked factor: NEAT

Megan sees this with clients constantly. Someone is still doing their regular workouts but has quietly dropped from 10,000 steps a day to 6,000 without realizing it. They feel like they're putting in the same effort, but their overall daily movement has decreased. Since NEAT happens across 12+ hours a day (compared to a single workout), even small drops can make a meaningful difference.

For many of Megan's clients, tracking daily steps outside of workouts and building in "exercise snacks" throughout the day — walking meetings, a standing desk, pacing during phone calls — is one of the most effective adjustments they can make.

What actually supports metabolism (and what's overhyped)

There are plenty of products promising to "boost" or "fix" your metabolism. Most are overhyped. The real levers are simpler — and more effective:

• Protect lean muscle mass through adequate protein and resistance training. Muscle is metabolically active tissue, and preserving it helps keep your resting metabolic rate higher.
• Eat enough. Chronically underfueling doesn't speed things up — it pushes all four metabolic buckets in the wrong direction. Megan recommends finding a gentle deficit you can maintain rather than continuously slashing calories.
• Prioritize protein. Beyond muscle preservation, protein has the highest thermic effect of food, meaning it costs more energy to process.
• Protect your NEAT. Track your daily movement outside of workouts and build in consistent activity throughout the day.
• Think in years, not weeks. A sustainable pace (half a pound to one pound per week) may feel slow, but it protects muscle, supports hormone and bone health, and leads to results that last.

Q&A highlights

I'm losing half a pound to a pound a week but wish I were losing more in the belly area. That rate of loss is actually in the ideal range — steady, sustainable, and protective of lean muscle. Unfortunately, where your body loses fat is largely influenced by genetics and hormones. The abdominal area is often one of the last places to change, especially for women in perimenopause. You can't spot-reduce, but as overall body composition shifts, the belly area will follow. It just may take more patience.

If my metabolism adapts, does that mean it's damaged? No. Metabolic adaptation is not metabolic damage. It's your body responding to changes in energy intake and body size to keep you alive and healthy. It's not permanent — when your environment, intake, and behaviors change, your metabolism can shift again.

Do I need to eat less and less to keep losing weight? This is one of the most common beliefs and one of the biggest reasons people get stuck. Continually cutting calories pushes all four metabolic buckets in the wrong direction and can impact bone health, hormone health, and thyroid function. A better approach is to find a gentle deficit (Megan usually doesn't take clients below about 1,800 calories) and then focus on the other levers — protein, NEAT, strength training, and body composition.

My weight has plateaued — does that mean my metabolism slowed down? Not necessarily. Plateaus are normal and often reflect your body reaching a new equilibrium. Before reacting drastically, check your consistency with protein, strength training, NEAT, and overall habits. Sometimes the adjustment is small. And if you're within 5–10 pounds of your goal but feeling strong, energetic, and healthy — it may be worth pausing to consider whether your body is telling you this is a good place to be.

Have questions? Email our care team at care@joinbelle.com or visit your Belle patient portal. Weekly live sessions with Megan are held every Thursday at 11 AM MT.