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 weight loss. It’s more precise than calorie counting alone because it helps you control where your calories come from, which affects how much muscle you keep, how full you feel, and how your energy holds up while losing weight. The process involves four steps: finding your calorie target, choosing a macro split, converting percentages into grams, and tracking your food.
Why Macros Matter More Than Just Calories
Every food you eat is made up of three macronutrients, each with a different calorie density. Protein has 4 calories per gram. Carbohydrates also have 4 calories per gram. Fat has 9 calories per gram, more than double the other two. This is why a tablespoon of olive oil and a cup of broccoli can have similar calorie counts despite being wildly different amounts of food.
Two people can eat 1,800 calories a day and get completely different results depending on their macro breakdown. Someone eating mostly carbs and fat with little protein will lose more muscle mass during a deficit. Someone hitting a higher protein target will preserve muscle, stay fuller between meals, and generally have an easier time sticking with the plan. Research consistently shows you can lose weight at various macro ratios, but the composition of what you lose (fat versus muscle) shifts depending on how much protein you’re getting.
Step 1: Find Your Calorie Target
Before you can set macro targets, you need a daily calorie number. Start by estimating your resting metabolic rate, the calories your body burns just keeping you alive. The most widely used formula is the Mifflin-St. Jeor equation:
- Men: (9.99 × weight in kg) + (6.25 × height in cm) − (4.92 × age) + 5
- Women: (9.99 × weight in kg) + (6.25 × height in cm) − (4.92 × age) − 161
To convert pounds to kilograms, divide by 2.2. To convert inches to centimeters, multiply by 2.54. So a 35-year-old woman who weighs 170 pounds (77 kg) and stands 5’6″ (168 cm) would calculate: (9.99 × 77) + (6.25 × 168) − (4.92 × 35) − 161 = roughly 1,448 calories at rest.
That resting number doesn’t include movement. Multiply it by an activity factor to get your maintenance calories: 1.2 for sedentary (desk job, little exercise), 1.375 for lightly active (exercise 1 to 3 days per week), 1.55 for moderately active (exercise 3 to 5 days), or 1.725 for very active (hard exercise 6 to 7 days). Our example woman with light activity: 1,448 × 1.375 = roughly 1,990 maintenance calories.
For weight loss, subtract 300 to 500 calories from that maintenance number. That puts our example at about 1,500 to 1,700 calories per day. Don’t go below 1,200 calories, as eating less than that increases the risk of constant hunger, nutrient gaps, and overeating rebounds.
Step 2: Choose Your Macro Split
The Dietary Guidelines for Americans suggest 45 to 65% of calories from carbohydrates, 20 to 35% from fat, and 10 to 35% from protein. Those are broad ranges. For weight loss specifically, you’ll want to push protein toward the higher end of that range and adjust carbs and fat to fill the remaining calories.
A practical starting point for fat loss is 30% protein, 35% fat, and 35% carbohydrates. This isn’t the only split that works, but it prioritizes protein high enough to protect muscle while keeping fat and carbs balanced enough that meals feel satisfying. Some people prefer higher carbs and lower fat, others prefer the reverse. What matters most is hitting your protein target and staying within your total calorie budget. The carb-to-fat ratio is more about personal preference and what keeps you consistent.
Step 3: Convert Percentages to Grams
This is where the math gets concrete. Take your calorie target, apply each percentage, then divide by the calories per gram for that macro. Using our example woman at 1,600 calories with a 30/35/35 split:
- Protein: 1,600 × 0.30 = 480 calories ÷ 4 = 120 grams
- Fat: 1,600 × 0.35 = 560 calories ÷ 9 = 62 grams
- Carbs: 1,600 × 0.35 = 560 calories ÷ 4 = 140 grams
Those gram targets are what you’ll actually track each day. Write them down or plug them into a tracking app. You don’t need to hit these numbers perfectly. Staying within 5 to 10 grams of each target is close enough to get results.
A Quick Check on Protein
Your protein target should land somewhere between 1.2 and 2.2 grams per kilogram of body weight. For our 77 kg example, that’s 92 to 170 grams per day. The 120-gram target from the calculation above falls right in that range. If your percentage-based number comes out unusually low, set protein by body weight instead and divide the remaining calories between carbs and fat.
Spreading protein across three meals also matters. Studies show that eating more than 40 grams in a single sitting doesn’t provide additional muscle-preserving benefit compared to 15 to 30 grams per meal. So rather than loading 90 grams into dinner and skipping breakfast, aim for 30 to 40 grams at each meal.
Step 4: Track Your Food Accurately
A digital food scale is the single most useful tool for counting macros. Eyeballing portions is notoriously inaccurate, and measuring cups work poorly for dense foods like peanut butter, cheese, or rice. Weigh food in grams for the best consistency.
Whether you weigh food raw or cooked matters more than you’d think. Meat loses water when it cooks, shrinking by roughly 25 to 33%. Carb sources like rice and pasta do the opposite, absorbing water and expanding. A chicken breast that weighs 200 grams raw might weigh only 140 grams cooked, but the nutrition databases for “raw chicken breast” are based on that 200-gram weight. If you weigh it cooked and log it as raw, you’ll undercount your protein and calories.
The simplest rule: pick one method (raw or cooked) and match your tracking app entry to that method. Most nutrition labels and database entries specify whether values are for raw or cooked portions. Consistency is more important than perfection here. If you always weigh your chicken cooked, search for “cooked chicken breast” in your app and you’ll be fine.
Tracking Alcohol
Alcohol doesn’t fit neatly into the three macros. It contains 7 calories per gram, but since most tracking apps don’t have an alcohol macro, you need to assign those calories somewhere. The two common approaches: divide the total calories in a drink by 4 and log it as carbohydrates, or divide by 9 and log it as fat. A 150-calorie glass of wine, for example, would count as either 38 grams of carbs or 17 grams of fat. Neither method is perfect, but it keeps your calorie total honest.
Net Carbs vs. Total Carbs
If you’re reading food labels closely, you’ll notice that fiber and sugar alcohols are listed under total carbohydrates. Net carbs are calculated by subtracting fiber and sugar alcohols from total carbs. A protein bar with 24 grams of total carbs, 10 grams of fiber, and 8 grams of sugar alcohols would have only 6 net carbs.
For general weight loss macro counting, tracking total carbs is simpler and works fine. Net carbs become more relevant if you’re following a very low-carb or ketogenic approach where the distinction meaningfully affects your daily limit.
When to Adjust Your Macros
Your starting numbers won’t be your forever numbers. As you lose weight, your body burns fewer calories at rest, so the deficit that worked at 170 pounds may not produce the same results at 155 pounds. If your weight stalls for two to three weeks while you’re tracking consistently, it’s time to recalculate.
The first move is to re-run your calorie formula with your current weight. That alone often creates enough of a new deficit. If it doesn’t, trim another 100 to 200 calories, pulling from carbs or fat rather than protein. Protect your protein target throughout the process. Cutting protein during a plateau accelerates muscle loss, which further slows your metabolism and makes the plateau worse.
Adding more movement is the other lever. Increasing your daily step count or adding a workout session per week can restore a deficit without requiring you to eat less. Many people find a combination, eating slightly fewer calories and moving slightly more, easier to sustain than a large cut in either direction.