What Are Macros?
A Beginner's Guide to Counting Protein, Carbs, and Fats for Weight Loss
Macros, short for macronutrients, are the three main nutrients your body needs in large amounts to survive and thrive: protein, carbohydrates, and fats. Unlike micronutrients (vitamins and minerals), which you need in tiny amounts, macros provide the bulk of your daily energy and building blocks for every cell in your body.
If you've ever wondered why two people can eat the same number of calories but get completely different results, macros are the answer. A 2,000 calorie diet of mostly protein looks very different inside your body than 2,000 calories of mostly carbs. Your body composition, energy levels, hunger, and hormone function all depend on not just HOW MUCH you eat, but WHAT you eat.
Why Count Macros Instead of Calories? Calorie counting tells you the quantity of energy you're consuming. Macro counting tells you the quality. When you track macros, you automatically track calories too, but you also ensure your body gets the right fuel for your specific goals.
Protein: What It Does and Why You Need It
Protein is made up of amino acids, which are literally the building blocks of your body. Every time you move, think, or heal, your body is using protein. There are 20 amino acids, and 9 of them are "essential," meaning your body cannot make them and you must get them from food.
What Does Protein Do?
- Builds and repairs muscle tissue after workouts
- Supports immune function by creating antibodies
- Produces enzymes and hormones that regulate body functions
- Maintains healthy skin, hair, and nails
- Keeps you full longer than carbs or fats (highest satiety)
- Burns more calories during digestion (highest thermic effect)
The Thermic Effect
Protein has the highest thermic effect of any macronutrient. Your body burns 20-35% of protein's calories just digesting it. Compare this to carbs (5-10%) and fats (0-3%). This means 100 calories of chicken actually nets you only 65-80 calories after digestion.
Best Protein Sources
| Food | Serving | Protein | Calories |
|---|---|---|---|
| Chicken Breast | 4 oz | 35g | 165 |
| Eggs (whole) | 2 large | 12g | 140 |
| Greek Yogurt | 1 cup | 20g | 130 |
| Salmon | 4 oz | 25g | 180 |
| Lean Ground Beef (90%) | 4 oz | 23g | 170 |
| Cottage Cheese | 1 cup | 28g | 220 |
| Tofu (firm) | 4 oz | 11g | 90 |
Carbohydrates: Your Body's Main Energy Source
Carbohydrates are your body's preferred and most efficient source of energy. When you eat carbs, your body breaks them down into glucose (blood sugar), which fuels everything from your brain to your muscles. Your brain alone uses about 120 grams of glucose per day.
The Three Types of Carbs
🍚 Starches
Complex carbs that provide sustained energy
- Rice (white and brown)
- Potatoes and sweet potatoes
- Oats and oatmeal
- Bread and pasta
- Beans and lentils
- Corn and peas
🍎 Sugars
Simple carbs that provide quick energy
- Fruit (fructose)
- Milk (lactose)
- Table sugar (sucrose)
- Honey and maple syrup
- Candy and soda (added sugars)
🥦 Fiber
Indigestible carbs that aid digestion
- Vegetables
- Whole grains
- Nuts and seeds
- Legumes
- Fruit skins
Net Carbs vs Total Carbs: Since fiber is not digested or absorbed, many people subtract fiber from total carbs to get "net carbs." This is especially relevant for keto and low-carb diets. For example, if a food has 20g carbs and 8g fiber, it has 12g net carbs.
Good Carbs vs. Bad Carbs
Not all carbs are created equal. The key difference is how quickly they raise your blood sugar:
| Good Carbs (Complex) | Bad Carbs (Simple/Refined) |
|---|---|
| Digest slowly, steady energy | Digest quickly, energy spike and crash |
| High in fiber and nutrients | Low in fiber, stripped of nutrients |
| Keep you full longer | Leave you hungry soon after |
| Examples: oats, quinoa, vegetables, fruit | Examples: white bread, candy, soda, pastries |
Fats: Why Dietary Fat Is Essential
Dietary fat was demonized for decades, but we now know that fat is absolutely essential for health. Your brain is nearly 60% fat. Every cell membrane in your body requires fat. And without fat, you cannot absorb vitamins A, D, E, and K.
Why You Need Fat
- Hormone production: Testosterone, estrogen, and cortisol all require fat
- Brain function: Your brain is mostly fat and needs it to operate
- Vitamin absorption: Fat-soluble vitamins (A, D, E, K) need fat to be absorbed
- Satiety: Fat helps you feel satisfied after meals
- Cell structure: Every cell membrane is made of fatty acids
Types of Fat
✅ Unsaturated (Good)
Heart-healthy fats to emphasize
- Olive oil
- Avocados
- Nuts (almonds, walnuts)
- Fatty fish (salmon, mackerel)
- Seeds (chia, flax)
⚠️ Saturated (Moderate)
Limit to less than 10% of calories
- Butter
- Red meat fat
- Cheese
- Coconut oil
- Whole milk
❌ Trans Fats (Avoid)
Artificial fats with no safe level
- Partially hydrogenated oils
- Some margarines
- Fried fast food
- Some baked goods
- Packaged snacks
How to Calculate Your Macros
Calculating your macros is a four-step process. First, you find your maintenance calories (how much you burn daily). Then, you adjust based on your goal. Finally, you divide those calories into protein, carbs, and fats.
Calculate BMR
Find your Basal Metabolic Rate (calories burned at rest)
Find TDEE
Multiply BMR by activity factor to get Total Daily Energy Expenditure
Adjust for Goal
Subtract for fat loss, add for muscle gain, or keep for maintenance
Split into Macros
Divide total calories into protein, carbs, and fats
The Formulas
Women: (10 × weight in kg) + (6.25 × height in cm) - (5 × age) - 161
Lightly Active (1-3 days/week): BMR × 1.375
Moderately Active (3-5 days/week): BMR × 1.55
Very Active (6-7 days/week): BMR × 1.725
Athlete (2x per day): BMR × 1.9
Maintenance: TDEE (stay the same)
Muscle Gain: TDEE + 250-500 calories
Fats: 0.3-0.4g per pound of bodyweight
Carbs: Remaining calories ÷ 4
Example Calculation
Let's calculate macros for a 30-year-old woman, 5'5" (165cm), 150 lbs (68kg), moderately active, with a fat loss goal:
| Step 1: BMR | (10 × 68) + (6.25 × 165) - (5 × 30) - 161 = 1,362 calories |
| Step 2: TDEE | 1,362 × 1.55 = 2,111 calories |
| Step 3: Fat Loss Target | 2,111 - 500 = 1,611 calories |
| Step 4: Protein | 150 lbs × 0.8g = 120g protein (480 calories) |
| Step 4: Fats | 150 lbs × 0.35g = 53g fat (477 calories) |
| Step 4: Carbs | (1,611 - 480 - 477) ÷ 4 = 163g carbs (654 calories) |
Final Macros: 120g Protein | 163g Carbs | 53g Fat | 1,611 Calories
Macro Ratios by Goal
Your ideal macro split depends on your goal. Here are the most common approaches:
🔥 Fat Loss
High protein preserves muscle during a deficit
💪 Muscle Gain
Higher carbs fuel intense training and recovery
⚖️ Maintenance
Balanced approach for long-term health
🥑 Keto
Under 50g carbs to maintain ketosis
🏃 Endurance
High carbs for sustained aerobic activity
🍖 Carnivore
Zero plant foods, meat and animal products only
Common Macro Myths Debunked
"Carbs make you fat"
Myth: Carbohydrates cause weight gain.
Fact: Excess calories cause weight gain, not carbs specifically. Carbs are stored as glycogen in muscles and liver. Only when glycogen stores are full AND you're in a calorie surplus do carbs convert to fat. Many lean athletes eat 300-500g carbs daily.
"Eating fat makes you fat"
Myth: Dietary fat turns into body fat.
Fact: Your body doesn't directly store dietary fat as body fat. Fat is broken down into fatty acids and used for energy, hormones, and cell function. Excess calories from ANY macro (including protein) can be stored as body fat.
"You can only absorb 30g of protein per meal"
Myth: Any protein over 30g is wasted.
Fact: Your body can absorb virtually unlimited protein. The 30g myth comes from muscle protein synthesis research, which does plateau around that amount. But absorbed protein still provides satiety, energy, and amino acids for other functions. Nothing is wasted.
"You need to eat every 2-3 hours to keep your metabolism up"
Myth: Frequent meals boost metabolism.
Fact: Meal frequency has no impact on metabolic rate. What matters is total daily intake. Whether you eat 6 small meals or 2 large meals, the thermic effect is the same if the macros are the same. Eat on whatever schedule works for your lifestyle.
Tips for Tracking Success
📱 Use a Tracking App
MyFitnessPal, Cronometer, or MacroFactor make tracking easy. Scan barcodes, save meals, and see your daily totals at a glance.
⚖️ Weigh Your Food
A $15 food scale is the best investment you can make. Eyeballing portions is notoriously inaccurate. Weigh everything for at least the first few weeks.
📝 Plan Ahead
Log your food the night before or morning of. This way you can adjust portions throughout the day instead of scrambling at dinner.
🎯 Prioritize Protein
Hit your protein goal first. It's the hardest macro to get enough of and the most important for body composition. Plan protein at every meal.
🍳 Meal Prep
Cooking in bulk ensures you always have macro-friendly options ready. Prep proteins, grains, and veggies for the week ahead.
📊 Track Trends, Not Days
One day over or under won't matter. Look at your weekly averages. Aim to hit your targets 80% of the time.
🍽️ Eat Out Smart
Most chain restaurants have nutrition info online. Look up the menu before you go and pre-log your order.
🔄 Adjust as Needed
If you're not seeing results after 2-3 weeks, adjust. Not losing? Cut 100-200 calories. Always hungry? Add more protein or fiber.
You don't have to be perfect. You just have to be aware. Once you understand what's in your food, the right choices become obvious.
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