Macronutrients

Macronutrients — protein, carbohydrates, and dietary fat — are the three nutrients your body needs in large amounts, and they’re the only ones that supply energy (calories). Getting your total calories right drives whether you gain, lose, or maintain weight, but how you split those calories across the macros decides how you feel, how you perform, and — critically when you’re dieting — how much muscle you keep.

This lesson breaks down what each macro does, roughly how much you need, and how to set targets that actually fit your goal. If you haven’t worked out your maintenance calories yet, start with BMR & TDEE — your macros are built on top of that number.

Protein

Protein is the single most important macro when you’re in a calorie deficit. It supplies amino acids for repairing and building muscle tissue, and a higher intake directly protects lean mass while you lose fat. It’s also the most satiating macro, so it helps blunt hunger.

For most people who train, aim for roughly 1.6–2.2 g of protein per kg of bodyweight per day. The leaner you are and the more aggressive your deficit, the closer to the top of that range you want to be. Protein provides 4 kcal/g.

Good sources: chicken, turkey, lean beef, fish, eggs, Greek yogurt, cottage cheese, tofu, tempeh, edamame, lentils, and whey or soy protein powder.

💡 Tip: If you only optimize one macro while cutting, make it protein. Hit your protein target every day before worrying about the rest.

Carbohydrates

Carbs are your body’s primary fuel for moderate-to-high intensity training. They top up muscle glycogen, which powers hard sets and lets you keep your performance — and therefore your muscle-retention stimulus — high in a deficit.

Carbs are not inherently fattening. Excess total calories cause fat gain; carbohydrate is simply a convenient, performance-friendly energy source. Prioritize fiber-rich, minimally processed options most of the time — whole grains, oats, potatoes, rice, fruit, beans, and vegetables — and aim for adequate fiber (roughly 25–38 g/day) for digestion and fullness. Carbs provide 4 kcal/g.

Dietary Fat

Dietary fat is essential — it supports hormone production (including testosterone and estrogen), cell membranes, and the absorption of fat-soluble vitamins (A, D, E, K). Cutting fat too low can blunt hormones and leave you feeling flat.

Set a floor of roughly 0.6–1 g of fat per kg of bodyweight per day and don’t dip below it for long, even when calories are tight. Favor sources like olive oil, avocado, nuts, seeds, and fatty fish. Fat is the most energy-dense macro at 9 kcal/g, so it’s easy to overshoot your calories if you’re not tracking it.

⚠️ Note: Very-low-fat diets are not “healthier” by default. Going under your fat floor for weeks can disrupt mood, hormones, and recovery.

Setting Your Macros

A simple, reliable order: set protein first, set a fat floor second, then let carbohydrates fill the rest of your calories.

Protein: bodyweight (kg) × 1.6–2.2 g.
Fat: bodyweight (kg) × 0.6–1 g (start near the middle).
Carbs: subtract protein and fat calories from your daily target, then divide the remainder by 4.

Macro	Energy	Suggested intake	Main role
Protein	4 kcal/g	1.6–2.2 g/kg/day	Preserve & build muscle; satiety
Carbohydrate	4 kcal/g	Fill remaining calories	Training fuel; fiber; performance
Dietary fat	9 kcal/g	0.6–1 g/kg/day (floor)	Hormones; vitamin absorption

Don’t want to do the math by hand? The free Macro calculator sets all three targets from your weight and goal in seconds. To dial in the calorie number those macros sit inside, use the TDEE calculator.

This lesson is being expanded

This is the outline version. A full deep-dive — covering protein timing and distribution, carb cycling, fat quality (omega-3s and saturated fat), fiber strategy, and worked examples for cutting vs. bulking — is in progress.

Calculate your maintenance calories with the TDEE calculator
Set your protein target (1.6–2.2 g/kg) and hit it daily
Set a fat floor (0.6–1 g/kg) and stay above it
Fill the remaining calories with carbohydrates
Generate all three targets fast with the Macro calculator