BMR, Meal Timing, and Why Skipping or Overeating Leads to Fat Storage

Your metabolism is constantly at work, even when you’re resting. At the heart of this process is your Basal Metabolic Rate (BMR) — the amount of energy your body needs just to keep your organs functioning. Knowing your BMR helps you understand how much fuel your body needs and why how you eat — not just what you eat — matters for maintaining a healthy weight and body composition.

What is BMR?

Your BMR (Basal Metabolic Rate) is the energy your body uses at rest to sustain life. It powers your brain, heart, lungs, liver, kidneys, and other vital organs. BMR makes up around 60–70% of your daily energy expenditure, meaning most of the calories you burn each day come from simply staying alive, not moving.

• Women: BMR ≈ 22 × body weight (kg)
• Men: BMR ≈ 24 × body weight (kg)

Example: A 70 kg woman has a BMR of roughly 1,540 calories/day — before walking, working, or exercising.

REMEMBER - this is SO approximate and is a very difficult individual number to  get accurate so this is a very general guideline.  If you have a smart watch - this would give you a more accurate approximate number

How to Find Your BMR on Your Apple Watch

Your Apple Watch can estimate your BMR based on your personal stats and activity:

1. Open the Health app on your iPhone.
2. Tap Browse → Body Measurements → Basal Energy.
3. You’ll see your daily BMR estimate — the calories your body burns at rest.
4. To calculate total daily energy expenditure, add your Active Energy (from movement) to your Basal Energy.

✅ Tip: Keep your Health Profile updated with age, height, weight, and gender for the most accurate estimate.

Things That Affect BMR

Your BMR isn’t fixed — it changes with lifestyle and body composition.

Factors that slow it down:

• Low muscle mass
• Chronic calorie restriction
• Ageing
• Poor sleep and high stress
• Low protein intake
• Sedentary lifestyle

Factors that boost it:

• Strength training and building muscle
• Eating sufficient protein
• Staying hydrated
• Regular movement throughout the day
• Adequate sleep
• Incidental exercise and movement - this is why we love our steps!!!

Why Meal Timing Matters: Skipping Meals & Overeating

Here’s where BMR and body fat storage intersect. Even if your total calories are appropriate for your BMR, how you distribute them across the day matters:

• Skipping meals: If you go long periods without eating, your body doesn’t get the fuel it needs. It compensates by slowing metabolism and storing more of the next meal as body fat.
• Overeating at one meal: Piling too many calories into one sitting overwhelms your body’s ability to use them efficiently. Excess energy is stored as fat, even if you don’t exceed your daily total calories.

The solution? Spread energy intake across the day and allow a few hours between meals for digestion and absorption. This keeps metabolism active and energy available when you need it.

A Balanced Day of Energy Intake

Here’s an example for someone eating ~1800 calories/day:

By spacing meals and snacks evenly, your body can efficiently use fuel instead of storing it as fat, keeping energy steady and metabolism active.

Key Takeaways

• BMR is the foundation of metabolism — it determines how much energy your body needs at rest.
• Meal timing matters: skipping meals or overeating at one sitting can lead to excess body fat storage, even if your total daily calories are reasonable.
• Spread your meals and snacks evenly across the day to support stable energy, healthy digestion, and efficient fat metabolism.
• Track your BMR with tools like your Apple Watch and check food labels to stay aware of calorie intake and plan meals realistically.