Counting macros means tracking the grams of protein, carbohydrates, and fat you eat each day, then adjusting those numbers to create a calorie deficit that drives fat loss. It’s more precise than calorie counting alone because where your calories come from affects how much muscle you keep, how full you feel, and how your body processes energy. The basic process has four steps: find your calorie target, set your protein, set your fat, then fill the rest with carbs.
Start With Your Calorie Target
Before you split anything into macros, you need to know how many calories your body burns in a day. This number, called your total daily energy expenditure (TDEE), accounts for both your resting metabolism and your activity level. The most validated formula for estimating resting metabolism is the Mifflin-St Jeor equation, which a comparative study found predicts resting metabolic rate within 10% of measured values more reliably than other common formulas.
Here’s how it works. For women: (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161. For men: same formula, but add 5 instead of subtracting 161. That gives you resting calories. Then multiply by an activity factor:
- Sedentary (desk job, little exercise): multiply by 1.2
- Lightly active (exercise 1–3 days/week): multiply by 1.375
- Moderately active (exercise 3–5 days/week): multiply by 1.55
- Active (exercise 6–7 days/week): multiply by 1.725
To lose about 1 to 2 pounds per week, which the CDC identifies as the pace most likely to stick long term, subtract 500 calories from your TDEE. A 500-calorie daily deficit works out to roughly one pound of fat loss per week. If your TDEE is 2,200, your target intake would be around 1,700 calories. That’s the number you’ll divide into macros.
Set Protein First
Protein is the most important macro to get right during a deficit because it protects your muscle mass while you lose fat. It also keeps you fuller than the same number of calories from carbs or fat. And your body burns significantly more energy digesting protein: 20 to 30% of the calories in protein are used up just processing it, compared to 5 to 10% for carbs and 0 to 3% for fat. That thermic effect gives you a small but real metabolic advantage.
Research on body composition during weight loss recommends 1.6 to 2.4 grams of protein per kilogram of body weight per day. If you’re newer to tracking or don’t do much resistance training, the lower end (1.6 g/kg) is a reasonable starting point. If you lift weights regularly or have a larger deficit, aim closer to 2.0 g/kg or above. For a 170-pound person (about 77 kg), that works out to roughly 123 to 185 grams of protein daily. Each gram of protein has 4 calories, so at 150 grams, you’d be spending 600 calories on protein.
Set Your Fat Minimum
Fat is essential for producing hormones, absorbing fat-soluble vitamins (A, D, E, and K), and keeping your brain and cell membranes functioning properly. Cutting it too low can disrupt hormone levels, particularly reproductive hormones. The general guideline for maintaining hormonal health is around 0.8 to 1 gram of fat per kilogram of body weight. For that same 77 kg person, that’s 62 to 77 grams of fat per day.
Since fat contains 9 calories per gram (more than double what protein or carbs provide), those grams add up quickly. At 70 grams of fat, you’re looking at 630 calories. The federal dietary guidelines suggest adults get 20 to 35% of total calories from fat, so your fat target will typically fall somewhere in that range naturally once you set it by body weight.
Fill the Rest With Carbs
Once protein and fat are set, the remaining calories go to carbohydrates. This isn’t because carbs are less important. They fuel your workouts, support brain function, and make your diet more enjoyable. They’re simply the most flexible macro, which is why they get assigned last.
The math is straightforward. Take your total calorie target, subtract your protein calories, subtract your fat calories, and divide what’s left by 4 (since carbs also provide 4 calories per gram). Using the example above with a 1,700-calorie target, 600 calories from protein, and 630 from fat, you’d have 470 calories left. That’s about 118 grams of carbs.
Here’s a quick summary of that example for a moderately active 170-pound person cutting at 1,700 calories:
- Protein: 150 g (600 calories)
- Fat: 70 g (630 calories)
- Carbs: 118 g (470 calories)
Your specific numbers will shift depending on your size, activity level, and preferences. Someone who does high-intensity training might want more carbs and slightly less fat. Someone who feels more satisfied on higher-fat meals can raise fat a bit and lower carbs. The protein target is the one number worth keeping firm.
How to Track Daily
Most people use an app like MyFitnessPal, Cronometer, or MacroFactor. You log each food you eat, and the app tallies your running totals for protein, fat, and carbs. A food scale is the single biggest accuracy upgrade. Eyeballing portions can easily be off by 20 to 30%, and those errors compound across a full day of eating.
Weigh foods raw whenever possible, since cooking changes water content and weight. Two ounces of dry pasta and two ounces of cooked pasta are very different amounts of food. For packaged items, use the nutrition label, but be aware of built-in rounding. FDA rules allow foods with fewer than 5 calories per serving to be labeled as zero calories, and fats below 0.5 grams per serving can also be listed as zero. A cooking spray with a tiny serving size might claim zero fat and zero calories, but use ten sprays and you’ve added a meaningful amount. Multiply small servings by the number you actually use to stay accurate.
You don’t need to hit your targets to the exact gram. Staying within 5 to 10 grams on each macro is close enough for consistent results. And if one day is off, it’s the weekly average that matters most.
Total Carbs vs. Net Carbs
You’ll see “net carbs” on some food labels and in certain tracking apps. Net carbs are calculated by subtracting fiber and sugar alcohols from total carbohydrates. The logic is that fiber and sugar alcohols don’t significantly raise blood sugar, so they pass through your system without contributing meaningful energy. A bar with 24 grams of total carbs but 10 grams of fiber and 8 grams of sugar alcohols would claim only 6 net carbs.
For straightforward macro counting aimed at weight loss, tracking total carbs is simpler and works fine. Net carbs matter more for people managing blood sugar, such as those following a ketogenic diet or living with diabetes. If you’re just looking to hit a daily carb target in a balanced deficit, total carbs keep things consistent.
Adjusting Over Time
Your starting numbers are an estimate. After two to three weeks of consistent tracking, check your results. If you’re losing 1 to 2 pounds per week, your macros are working. If the scale isn’t moving, your calorie target is likely too high, or your tracking has gaps. Before cutting calories further, make sure you’re weighing foods, counting cooking oils, and logging everything including drinks, sauces, and snacks.
If you do need to adjust, reduce by 100 to 150 calories at a time, pulling from carbs or fat while keeping protein steady. As you lose weight, your TDEE drops because a smaller body burns fewer calories at rest. Expect to recalculate every 10 to 15 pounds lost, or whenever progress stalls for more than two weeks despite accurate tracking.
Protein stays at 1.6 to 2.4 g/kg throughout. In fact, as calories get lower, keeping protein at the higher end of that range becomes more important for holding onto muscle. If you’re also strength training during your cut (which you should be, if possible), that combination of high protein and resistance work is the most effective strategy for losing fat while preserving the lean mass underneath.