Your macros depend on your goal, but the standard healthy ranges are 45–65% of calories from carbohydrates, 20–35% from fat, and 10–35% from protein. These ranges, set by the National Academies of Sciences and referenced in the Dietary Guidelines for Americans, are broad on purpose. Where you land within them depends on whether you’re trying to lose fat, build muscle, fuel intense training, or simply eat well.
The Baseline Ranges for General Health
If you don’t have a specific fitness goal and just want a balanced diet, the Acceptable Macronutrient Distribution Ranges (AMDR) are your starting point:
- Carbohydrates: 45–65% of total calories
- Fat: 20–35% of total calories
- Protein: 10–35% of total calories
For someone eating 2,000 calories a day, the midpoint of these ranges works out to roughly 250 grams of carbs, 65 grams of fat, and 100 grams of protein. That’s a reasonable split for maintaining your weight and covering basic nutritional needs without overthinking things.
The minimum protein recommendation is 0.8 grams per kilogram of body weight, which translates to about 0.36 grams per pound. For a 160-pound person, that’s only 58 grams of protein per day. This is the floor for meeting basic biological needs, not a target for anyone who exercises regularly or wants to change their body composition.
Macros for Losing Fat
Macro ratios matter during fat loss because the wrong balance can cost you muscle. When you eat fewer calories than you burn, your body pulls energy from both fat stores and lean tissue. The single most important macro adjustment you can make is increasing protein, which protects muscle while you’re in a deficit.
Research supports eating 1.2 to 2.0 grams of protein per kilogram of body weight for fat loss with muscle retention. For a 170-pound person (about 77 kg), that’s 92 to 154 grams of protein daily. If you’re strength training while dieting, aim for the higher end of that range. After setting protein, fill the remaining calories with a mix of carbs and fats that feels sustainable. A common split for fat loss looks like 30% protein, 35–40% carbs, and 25–30% fat, though the exact percentages matter less than consistently hitting your protein target and staying in a calorie deficit.
One thing to keep in mind: your macros aren’t set-and-forget numbers. As you lose weight, your metabolic rate drops proportionally. The calorie intake that created a deficit at 200 pounds may put you at maintenance by 180 pounds. Tracking your progress every few weeks and recalculating when weight loss stalls keeps things moving. Periodically bringing calories back up to maintenance for a few days to two weeks can also help with adherence and may reduce some of the metabolic slowdown that comes with prolonged dieting.
Macros for Building Muscle
Building muscle requires a calorie surplus, and the quality of those extra calories determines whether you add mostly muscle or mostly fat. Protein remains important here, with the same 1.2 to 2.0 grams per kilogram range serving as a solid guideline. Going much beyond 2.0 g/kg doesn’t appear to produce additional muscle-building benefits for most people.
Carbohydrates play a bigger role during a building phase than during fat loss. Carbs fuel resistance training and help your muscles recover afterward, so this is the time to push toward the higher end of the 45–65% carbohydrate range. Fat can sit at the lower end of its range, around 20–25% of calories, as long as you’re still getting enough to support hormone production. A practical muscle-building split for someone training hard might look like 25–30% protein, 45–55% carbs, and 20–25% fat.
Macros for Endurance and High-Intensity Training
Athletes and serious recreational exercisers burn through carbohydrate stores quickly. Carbohydrate needs scale with training volume, ranging from 6 to 10 grams per kilogram of body weight depending on total training load and intensity. For a 150-pound (68 kg) runner logging heavy mileage, that could mean 400 to 680 grams of carbs per day, well above what a sedentary person needs.
During exercise lasting more than an hour, consuming 30 to 60 grams of carbs per hour helps maintain blood glucose and performance. After training, the priority is refueling: 1.0 to 1.5 grams of carbs per kilogram within the first 30 minutes, then repeating every two hours for four to six hours. This replenishment schedule matters most for people training multiple times per day or on consecutive days. If you work out three or four times a week at moderate intensity, a standard macro split with carbs toward the higher end of the AMDR (55–65%) will typically cover your needs.
How to Calculate Your Starting Numbers
Before you can turn percentages into grams, you need a calorie target. The most common method is estimating your basal metabolic rate (the calories your body burns at rest) and then multiplying by an activity factor to get your total daily energy expenditure, or TDEE. Several online calculators do this automatically using formulas like the Mifflin-St Jeor equation, which accounts for your age, sex, height, and weight.
These calculators are estimates, not precise measurements. They tend to underestimate needs for people who are underweight and overestimate for people with a BMI over 30. Treat the number you get as a starting point and adjust based on what actually happens over two to three weeks. If you’re trying to lose weight and the scale isn’t budging, you’re likely eating at or above maintenance regardless of what the calculator said.
Once you have a calorie target, converting to grams is straightforward. Protein and carbohydrates each contain 4 calories per gram, and fat contains 9 calories per gram. If your target is 2,000 calories with a 30/40/30 split (protein/carbs/fat):
- Protein: 2,000 × 0.30 = 600 calories ÷ 4 = 150 grams
- Carbs: 2,000 × 0.40 = 800 calories ÷ 4 = 200 grams
- Fat: 2,000 × 0.30 = 600 calories ÷ 9 = 67 grams
When to Recalculate
Your macros should evolve as your body and goals change. A few signals that it’s time to recalculate: you’ve lost or gained more than 10 pounds, your training volume has shifted significantly, or you’ve been stuck at a plateau for more than two to three weeks despite consistent tracking. As weight drops, your resting metabolic rate decreases, so the same calorie and macro targets that worked at your starting weight will eventually stop producing results.
Non-exercise activity, the calories you burn walking around, fidgeting, and doing daily tasks, also tends to drop as you diet. This is partly unconscious. Monitoring your daily step count and keeping it stable (or slightly increasing it) can offset some of this effect. If you’ve been in a deficit for several months, cycling calories up to maintenance for one to two weeks gives your body a metabolic and psychological break before resuming.
The best macro split is ultimately the one you can follow consistently. A theoretically perfect ratio that you abandon after two weeks does less for you than a “good enough” split you stick with for months. Start with the ranges above, track your food for a few weeks, and let the results guide your adjustments.