Best Macros for Weight Loss: How to Set Yours

The best macros for weight loss start with enough protein: about 1.2-1.6 g per kg of body weight a day (0.54-0.73 g per lb). Keep fat at 20-35% of calories and give the rest to carbs. A common starting split is 30% protein, 40% carbs and 30% fat.

The split matters less than two things: eating fewer calories than you burn, and hitting your protein number most days.

Key takeaways

• Calories decide weight loss; macros mostly decide how much of it is fat and how full you feel.
• Protein first: 1.2-1.6 g/kg a day while dieting, and up to about 2.2 g/kg if you lift weights.
• Stay inside the ranges: protein 10-35%, fat 20-35% and carbs 45-65% of calories are the adult ranges set by the Institute of Medicine. A 30% protein split puts carbs at about 40%, slightly under that range.
• Low carb vs low fat is a tie: a 12-month trial found 6.0 kg vs 5.3 kg, not a meaningful difference.
• Recheck every 4-6 weeks and adjust calories, not just ratios.

Calories come first

Protein and carbs have 4 calories per gram, and fat has 9. A deficit of the same size produces about the same weight loss whatever the split.

Two large pieces of research make this clear:

• DIETFITS (Stanford, 2018): 609 adults followed a healthy low-fat diet (about 48% carbs, 29% fat, 21% protein) or a healthy low-carb diet (30% carbs, 45% fat, 23% protein) for a year. They lost 5.3 kg (11.7 lb) and 6.0 kg (13.2 lb), and the 0.7 kg gap was not statistically significant (Gardner and colleagues).
• Controlled feeding studies: a meta-analysis of 32 studies that swapped carbs for fat at equal calories found slightly more fat loss with the lower-fat diets, 16 g a day, the opposite of the low-carb claim (Hall and Guo, 2017).

Find your calorie target first. The TDEE guide walks through the math, and NIH guidance of about 500 calories a day below what you burn is a common starting deficit.

How to calculate your macros for weight loss

1. Set your calories. Estimate your TDEE and subtract about 500 calories.
2. Set protein. Multiply your weight in kg by 1.2-1.6 (or your weight in lb by 0.54-0.73). Multiply grams by 4 for calories.
3. Set fat. Choose 20-35% of your calories and divide by 9 for grams.
4. Fill the rest with carbs. Subtract protein and fat calories from your total and divide by 4.

Worked example

A 170-lb (77 kg) adult eating 1,800 calories a day:

All three land inside the adult ranges. The macro calculator runs these numbers for you.

How much protein should you eat to lose weight?

A 2015 review in the American Journal of Clinical Nutrition found that, in shorter, tightly controlled studies, higher-protein diets during calorie restriction led to more weight and fat loss and better lean-mass retention than lower-protein diets, with a modest effect on fullness (Leidy and colleagues). The range most often used is 1.2-1.6 g/kg a day.

If you have a lot of weight to lose, using your goal weight keeps the number realistic. The protein calculator gives a personal target, and our high-protein diet guide has food lists. If you have kidney disease, check with your doctor before raising protein.

Common macro ratios compared

Grams per day at three calorie levels (protein / carbs / fat).

When people say "40/30/30" they usually mean 40% carbs, 30% protein and 30% fat, the Zone diet split, which is the first row. Read the other way, 40% protein is above the 35% upper end of the adult range, and at 1,800 calories it means 180 g of protein, more than most people need. Percentages also scale oddly: at a low calorie target, 30% protein may be too little for a larger person. That's why setting protein in grams first works better.

Low carb vs low fat for weight loss

Choose the one you can keep up. In DIETFITS, neither genotype nor insulin response predicted who did better on which diet, and the average results were nearly identical. Low carb may suit people who prefer meat, eggs, cheese and vegetables; higher carb may suit people who train hard or like grains, fruit and beans. Our macros vs calories guide covers whether you need to track macros at all.

Macros if you lift weights

If you strength train, protein matters more:

• 1.4-2.0 g/kg a day is enough for most exercising people, according to the International Society of Sports Nutrition (Jager and colleagues, 2017).
• 2.3-3.1 g/kg a day may help resistance-trained people keep the most lean mass during a calorie deficit (same position stand). A review for bodybuilders applies this range to lean body mass rather than total weight and suggests losing 0.5-1% of body weight a week (Helms and colleagues, 2014).
• In a meta-analysis of 49 trials, extra protein with training stopped adding muscle above about 1.6 g/kg a day on average (Morton and colleagues, 2018).

Spread protein over 3-5 meals of 20-40 g each.

Fat and fiber minimums

• Fat: keep it at 20% of calories or more. That's 40 g a day at 1,800 calories. Fat carries vitamins A, D, E and K, and very low-fat diets are hard to stick with.
• Fiber: the Institute of Medicine sets 14 g per 1,000 calories, about 25 g at 1,800 calories. Beans, oats, berries and vegetables are the easiest sources, and they help with fullness.

How to adjust your macros

Weigh yourself several times a week and look at the 2-4 week trend, not single days. If you're losing about 0.5-1% of your body weight a week, keep going. If the trend stalls for 3-4 weeks, lower calories by 100-200 a day, usually from carbs or fat, and keep protein the same.

As you lose weight you also burn a bit less, so recheck your TDEE every 4-6 weeks. Our guide to metabolic adaptation explains why loss slows over time.

Common macro mistakes

• Cutting protein to save calories. Cut carbs or fat first.
• Going very low fat. Below 20% of calories, meals get less satisfying fast.
• Chasing a perfect ratio. Hitting calories and protein most days matters more than hitting carbs and fat to the gram.
• Never updating. A target set at 200 lb won't be right at 180 lb.
• Guessing portions. Oils, nut butters and dressings are where tracked and real intake drift apart. Logging in Nutrify by photo, barcode or voice shows your protein, carbs and fat against your targets as you go. For other options, see our macro tracking apps comparison.

Sources

• Institute of Medicine (National Academies). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. 2005. Acceptable Macronutrient Distribution Ranges and fiber Adequate Intake.
• Gardner CD, Trepanowski JF, Del Gobbo LC, et al. Effect of low-fat vs low-carbohydrate diet on 12-month weight loss in overweight adults: the DIETFITS randomized clinical trial. JAMA, 2018.
• Hall KD, Guo J. Obesity energetics: body weight regulation and the effects of diet composition. Gastroenterology, 2017.
• Leidy HJ, Clifton PM, Astrup A, et al. The role of protein in weight loss and maintenance. Am J Clin Nutr, 2015.
• Jager R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr, 2017.
• Helms ER, Aragon AA, Fitschen PJ. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. J Int Soc Sports Nutr, 2014.
• That Clean Life, 40-30-30 Weight Loss Diet (defines the split as 40% carbs, 30% protein, 30% fat).
• Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med, 2018.
• NIH News in Health, Healthy Weight Control, December 2022.