Macros Explained: Fueling Your Body Based on Composition, Not Just Weight
Body InsightMost nutrition plans focus on one number — weight. But your weight alone doesn’t tell you what you’re made of, or how to properly fuel your body.
That’s where macronutrients come in.
Macros help you target the right balance of fuel for your goals — whether you're trying to build muscle, reduce fat mass, improve metabolic health, or support performance. And when your macro intake is based on your actual body composition, it becomes far more effective and sustainable.
What Are Macronutrients?
Macronutrients (or "macros") are the three main nutrient types your body needs in large amounts:
Protein – for building, maintaining, and repairing lean tissue
Carbohydrates – your body’s preferred energy source
Fat – essential for hormone production, brain function, and cellular health
Each macronutrient provides calories:
Protein: 4 kcal per gram
Carbohydrates: 4 kcal per gram
Fat: 9 kcal per gram
But macros do more than supply energy — they shape your body’s structure, performance, and adaptation to training and recovery.
Why Macros Matter for Body Composition
A calorie is not just a calorie. The ratio of protein, carbs, and fats you consume determines:
Whether you maintain or lose muscle during fat loss
How much energy you have during training
How well you recover and rebuild afterward
Your ability to regulate hunger, metabolism, and hormones
A nutrition plan that only cuts calories — without adjusting macros — often leads to:
Muscle loss
Low energy
Poor recovery
Slow or unsustainable fat loss
What Each Macro Does in the Body
Protein
Builds and repairs muscle and connective tissue
Supports immune function, hormones, and enzymes
Helps preserve lean mass during fat loss
Increases satiety (keeps you full longer)
Burns more energy during digestion (thermic effect)
Essential for: Preserving lean mass, especially during a calorie deficit
Carbohydrates
Primary energy source for the brain and working muscles
Stored as glycogen in muscle and liver for quick access
Supports hormonal function and recovery
Often wrongly demonized — but essential in the right amounts
Essential for: Fueling workouts, brain function, and hormonal stability
Fat
Supports production of hormones like testosterone and estrogen
Essential for absorbing vitamins A, D, E, and K
Provides long-lasting energy
Helps protect organs and regulate inflammation
Essential for: Hormonal health, cell repair, and long-term energy
How to Set Your Macros Based on Body Composition
If you’ve had a DEXA scan, you already know your lean mass and fat mass — which makes your macro planning far more accurate.
Your macro breakdown should support one of three core goals:
1. Reducing Fat Mass (While Preserving Muscle)
Protein: 2.0–2.4g per kg of lean mass
Carbohydrates: Moderate — enough to support training and prevent muscle breakdown
Fat: Moderate — from quality sources like olive oil, nuts, fatty fish
Target: A mild, sustainable calorie deficit (~15–20%)
Strategy: Prioritize strength training and protein to hold onto lean mass
2. Building Lean Mass
Protein: 2.0–2.2g per kg of lean mass
Carbohydrates: Higher — to support muscle growth and glycogen replenishment
Fat: Moderate
Target: A slight calorie surplus (~10–15%)
Strategy: Use progressive overload in the gym and recovery-focused eating
3. Maintaining Body Composition
Protein: 1.6–2.0g per kg of lean mass
Carbohydrates: Moderate to high — based on training volume
Fat: Moderate
Target: TDEE (Total Daily Energy Expenditure)
Strategy: Stay consistent, monitor energy, performance, and lean mass
Note: These ranges are best dialed in using actual lean mass, not total body weight — which makes DEXA-based macro plans more precise than generic ones.
Why Macro Planning Is More Effective Than Calorie Counting Alone
Most generic diets fail because they:
Don’t differentiate between fat loss and weight loss
Don’t account for how muscle impacts metabolism
Use inaccurate estimates of calorie needs
Lead to poor energy, muscle loss, and yo-yo results
Macro planning based on body composition ensures:
Fat is the primary weight being lost (not muscle)
Muscle is preserved or gained
You’re eating in a way that supports your physiology and performance
What a Day of Macro-Aware Eating Looks Like
Here’s a sample breakdown for someone focused on fat loss, aiming for:
130g protein
160g carbohydrates
60g fat
Meal 1 (Breakfast)
3 eggs + 1 slice whole grain toast
1 cup spinach sautéed in olive oil
1 small banana
Meal 2 (Lunch)
Grilled chicken breast
Quinoa and roasted vegetables
Avocado
Meal 3 (Dinner)
Baked salmon
Sweet potato
Steamed broccoli
Olive oil drizzle
Snacks/Post-Workout
Whey protein shake
Greek yogurt with berries
Note: Exact numbers vary based on your lean mass, TDEE, and training.
Final Thought: Macros Build the Body You Want to Live In
If you want to change how your body performs, looks, and feels — you need to go beyond calories.
Macronutrients are the building blocks of:
Muscle
Metabolism
Recovery
Hormones
Energy
Long-term sustainability
And when your macro plan is built on your actual body composition, the results come faster — and last longer.
Ready to Personalize Your Macros?
Start with your DEXA scan to measure lean mass, fat mass, and resting metabolic rate.
From there, we’ll calculate a macro plan that reflects:
Your unique body composition
Your metabolism
Your goals
Book your scan today — and build a strategy that fuels the results you want, not just the weight you want to lose.
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