Figuring out your macros for weight loss comes down to three steps: estimate how many calories your body burns each day, subtract enough to create a deficit, then divide those remaining calories among protein, fat, and carbohydrates. The whole process takes about ten minutes with a calculator, and the numbers you land on will be far more useful than generic advice like “eat more protein and fewer carbs.”
Step 1: Estimate Your Daily Calorie Burn
Your body burns a baseline number of calories just keeping you alive: breathing, circulating blood, maintaining body temperature. This is your basal metabolic rate, or BMR. The most widely used formula to estimate it is the Harris-Benedict equation:
- Males: 88.362 + (13.397 × weight in kg) + (4.799 × height in cm) − (5.677 × age in years)
- Females: 447.593 + (9.247 × weight in kg) + (3.098 × height in cm) − (4.330 × age in years)
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 (77.3 kg) and stands 5’6″ (167.6 cm) would get a BMR of roughly 1,510 calories.
BMR only covers what your body burns at complete rest. To account for your actual daily movement, multiply it by an activity factor:
- Sedentary (desk job, no planned exercise): BMR × 1.2
- Lightly active (light exercise 1–3 days per week): BMR × 1.375
- Moderately active (moderate exercise 3–5 days per week): BMR × 1.55
- Very active (hard exercise 6–7 days per week): BMR × 1.725
The result is your total daily energy expenditure, or TDEE. For the woman in our example who exercises three days a week, that’s about 1,510 × 1.375 = 2,076 calories per day. This is the number you’ll build your macros around. Most people overestimate their activity level, so if you’re unsure, pick the lower option. You can always adjust later.
Step 2: Set Your Calorie Deficit
Cutting roughly 500 calories per day from your TDEE typically produces about half a pound to one pound of weight loss per week. For our example, that means a daily target of around 1,576 calories. This is a moderate, sustainable pace. Larger deficits speed things up on paper but make it harder to hold onto muscle and harder to stick with the plan long enough for it to matter.
A good rule of thumb: your deficit should not drop you below about 1,200 calories (for most women) or 1,500 calories (for most men). If the math puts you there, a smaller deficit combined with more movement is a better path forward.
Step 3: Divide Calories Into Macros
Every gram of protein contains 4 calories. Every gram of carbohydrate also contains 4 calories. Every gram of fat contains 9 calories. These conversion factors are how you’ll turn a calorie target into actual grams of food on your plate.
Protein First
Protein is the most important macro to get right during weight loss. It protects muscle mass while you’re in a deficit, keeps you fuller for longer, and burns more energy during digestion than fat or carbs do. The baseline recommendation for sedentary adults is 0.8 grams per kilogram of body weight, but that’s a minimum to prevent deficiency, not a target for someone actively losing weight.
If you exercise regularly, aim for 1.2 to 1.7 grams per kilogram, with the higher end for people who lift weights. Even if you don’t exercise much, bumping up to 1.1 to 1.5 grams per kilogram helps preserve lean mass during a deficit. For our 77.3 kg example, that’s roughly 93 to 116 grams of protein per day. Let’s say she picks 110 grams. At 4 calories per gram, that’s 440 calories allocated to protein.
Fat Second
Dietary fat supports hormone production, helps you absorb certain vitamins, and keeps your skin and brain functioning well. Cutting it too low causes real problems. The general recommendation for adults is 20 to 35 percent of total calories from fat, and a practical minimum for hormonal health is about 0.8 to 1 gram per kilogram of body weight.
For our example at 1,576 calories, 25 percent from fat would be 394 calories, or about 44 grams of fat (394 ÷ 9). That also happens to land right around 0.8 grams per kilogram for a 77 kg person, which is the lower end of the healthy range. If you feel better with more fat in your diet, going up to 30 or 35 percent is fine. You’ll just have fewer calories left for carbs.
Carbs Get the Remainder
After protein and fat are set, the remaining calories go to carbohydrates. For our example: 1,576 total − 440 protein − 394 fat = 742 calories from carbs. Divide by 4 calories per gram, and that’s about 185 grams of carbohydrates per day.
So the final macro targets for this person would be: 110g protein, 44g fat, 185g carbs, totaling roughly 1,576 calories. Carbs often feel like they’re getting “the leftovers,” but that’s by design. Protein and fat have minimum thresholds your body needs. Carbs are more flexible, and adjusting them up or down is the easiest way to fine-tune your calories.
A Quick Shortcut if the Math Feels Heavy
If running formulas isn’t your thing, a simpler starting point: aim for 1 gram of protein per pound of your goal body weight, keep fat at roughly 25 to 30 percent of your total calories, and fill the rest with carbs. This won’t be as precise, but it gets most people in the right ballpark and you can refine from there based on how your body responds over two to three weeks.
Tracking Accurately Makes or Breaks Results
The most carefully calculated macro targets won’t help if your tracking is off, and tracking errors are extremely common. A few of the biggest culprits:
Portion sizes drift quickly without a food scale. A tablespoon of peanut butter easily becomes two. Half a cup of rice turns into a full cup once it hits the bowl. Olive oil used for cooking adds up fast, often 100+ untracked calories per meal. A digital kitchen scale (measuring in grams) is far more reliable than measuring cups and eyeballing.
Small, unlogged extras accumulate throughout the day. Creamer in your coffee, a few bites while cooking, finishing your kid’s leftovers, sauces and condiments. These can add several hundred uncounted calories over the course of a day. Log cooking oils, dressings, and snacks, even the small ones.
If you use a tracking app, double-check the entries. Many food databases rely on user-submitted data, and the errors can be significant: chicken thighs listed with zero fat, oatmeal showing 20 grams of protein, wildly inaccurate totals for everyday foods. Cross-reference with the nutrition label on the actual packaging when possible.
One pattern worth noting: many people eat nutrient-dense foods but still consume more than their body needs, especially from calorie-dense “healthy” fats like nuts, avocado, and olive oil. Clean eating and eating in a deficit are two different things.
When to Adjust Your Numbers
Your starting macros are an educated guess. Give them at least two to three weeks before making changes, because day-to-day weight fluctuates with water retention, sleep, stress, and digestive timing. Track your weekly average weight instead of fixating on any single morning weigh-in.
If your weight hasn’t budged after three consistent weeks, you have two main levers: reduce carbs or fat by a small amount (cutting another 100 to 200 calories) or increase your activity. Keep protein where it is or even raise it slightly, since its role in preserving muscle becomes more important as your deficit gets larger.
Plateaus are also a good time to consider a brief diet break. Spending two to three days (or up to two weeks) eating at your maintenance calories can improve adherence and may help counteract some of the metabolic slowdown that happens during prolonged calorie restriction. This isn’t quitting. It’s a deliberate reset that often makes the next phase of fat loss more sustainable.
As you lose weight, your TDEE drops because there’s less of you to fuel. Recalculating every 10 to 15 pounds lost keeps your targets relevant. The macros you start with are a launching point, not a permanent prescription.