*Brendon Grew, a 3DMJ Athlete, eats enough protein to help him lose fat, not muscle, while dieting.*
When you’re in a caloric deficit, your body is eating you alive.
Your goal as a dieter is to make sure your body “eats” as much fat and as little muscle as possible.
One of the best ways to keep your body from devouring your muscle tissue is to give it another source of protein — dietary protein.1,2
Think of your caloric deficit as a lion that’s about to eat you. If you give the lion another source of meat, you might be able to get away without getting bitten.
Likewise, if you don’t eat enough protein while dieting, you’ll lose more muscle and less fat.
The problem is that your protein needs can change over time based on several factors, which can make it hard to pinpoint exactly how much you need to avoid muscle loss. Another problem is that most of the recommendations for protein are not designed for dieting athletes, like you.3-5
However, we do have enough research at this point to make some educated guesses as to how much protein you need to keep the lion happy.
3 Reasons You Probably Need More Protein than the Average Person
Researchers have used nitrogen balance studies to estimate the minimum amount of protein you need to stay reasonably healthy. These studies aren’t perfect, but they’re still a useful tool for determining your protein needs.3,4,6-8
They’ve used this data to develop what’s known as the “Recommended Daily Intake,” or “RDI, for protein.
The current RDI for protein is 0.8 grams per kilogram of body weight per day (g/kg/day). This is the minimum amount needed to keep 97.5% of people over the age of 19 healthy.3,4,9 It’s the standard protein intake for most diet recommendations.
If you’re sedentary or lightly active and not in a caloric deficit, you probably don’t need to eat much more protein than the RDI.
However, if you’re trying to lose fat while maintaining your muscle mass and athletic performance, there are three main reasons why the RDI is probably too low for you.
1. Your protein needs increase when you cut calories.
Your body is always breaking down and rebuilding tissues. When you’re in a caloric deficit, your rate of tissue breakdown rises above your rate of tissue growth, and you lose weight.10 You’ve let the lion out of the cage.
When this happens, your body loses more protein than it retains, and you need to eat more protein to maintain your lean body mass.11-14
When people restrict their calorie intake, those who eat more protein generally lose less muscle and more fat.2,15-23
In general, the larger your caloric deficit, the more your body tries to cannibalize your muscle tissue.24,25
Eating more protein can help prevent this to a degree, but after a point you’re probably going to lose some muscle mass if you cut calories low enough.
In most cases, overweight dieters need to eat at least 1.4-1.6 grams of protein per kilogram of body mass to avoid losing muscle.9,17,19,21 That’s about twice the RDI. If these people lift weights, they can usually eat slightly less because strength training also helps preserve muscle mass.26
2. Your protein needs increase as you get leaner.
The less body fat you have, the more protein you usually need to prevent muscle loss while dieting.3,6
When your body has thousands of extra calories stored as fat tissue, it’s generally less likely to break down your muscles. The reverse is also true, however.
Obese people can maintain their muscle mass while eating 800 calories per day, if they eat about 1.2 g/kg of protein and lift weights.26
Most studies indicate that leaner athletes may need more protein to prevent muscle loss when dieting to lower body fat levels.27,28 The most recent and comprehensive review, authored by Eric Helms, indicates that lean athletes need around 2.3-3.1 grams per kilogram of lean body mass to avoid losing muscle while dieting.6
That might seem like a lot, but it’s actually not that much more than obese people when you adjust for their body composition. For example, in one study obese women ate 1.6 grams of protein per kilogram of total body weight. When you apply this same amount to their lean body mass, however, it’s actually 3.2 grams per kilogram.19
Lean people probably need more protein than overweight people to avoid losing muscle while dieting. When you adjust for your lean body mass, however, the differences aren’t huge.
3. Your protein needs increase during intensive and/or high-volume progressive training.
If you’re challenging yourself with more volume, intensity, or variety in your training, you might need to eat more protein while dieting.
Even if you’re not in a caloric deficit, there’s good data that both strength and endurance athletes need more protein than the RDI to perform at their best.3-5,8,29
Dieting is another kind of stress, which probably increases your protein needs even more.3-5,8,30
If you want to maintain your muscle mass and performance while dieting, you also need to maintain the intensity of your training. Eating more protein probably makes that easier.
How to Set Your Protein Intake While Dieting
Here’s what we know so far.
- When you’re in a caloric deficit, you need to eat more protein than normal to avoid losing muscle mass. The larger your deficit, the more protein you generally need, to a point.
- If you’re leaner, you need more protein than overweight or obese people to avoid losing muscle.
- If you’re training hard while you’re in a caloric deficit, you probably need even more protein than normal to avoid losing muscle.
All of the above factors are also additive. If you’re in a large calorie deficit, you’re at a low body fat percentage, and you’re training hard, you’ll probably need a lot more protein than the standard RDI.
This doesn’t mean more is better for everyone, but lean, dieting athletes almost certainly need more protein than most other people.
Use this chart to estimate your protein needs:
|No calorie deficit, minimal training, or less focused on maintaining muscle mass.||1.2-2.0 g/kg|
|Small to moderate calorie deficit, with progressive training.||1.8-2.4 g/kg|
|Medium to large calorie deficit, with progressive training.||2.3-3.1 g/kg|
These values are for your lean body mass, not your total body mass.
Did you enjoy this article? Still interested in a more customized nutrition plan? Learn more about our nutrition services here.
1. Stiegler P, Cunliffe A. The role of diet and exercise for the maintenance of fat-free mass and resting metabolic rate during weight loss. Sports Med. 2006;36(3):239–262. Available at: https://goo.gl/RbLEX.
2. Westerterp-Plantenga MS, Lemmens SG, Westerterp KR. Dietary protein – its role in satiety, energetics, weight loss and health. Br J Nutr. 2012;108 Suppl 2:S105–12. doi:10.1017/S0007114512002589.
3. Phillips SM, van Loon LJC. Dietary protein for athletes: From requirements to optimum adaptation. J Sports Sci. 2011;29 Suppl 1(6):647–654. doi:10.1080/02640414.2011.619204.
4. Phillips SM. Dietary protein requirements and adaptive advantages in athletes. Br J Nutr. 2012;108 Suppl 2:S158–67. doi:10.1017/S0007114512002516.
5. Tipton KD, Wolfe RR. Protein and amino acids for athletes. J Sports Sci. 2004;22(1):65–79. doi:10.1080/0264041031000140554.
6. Helms ER, Zinn C, Rowlands DS, Brown SR. A Systematic Review of Dietary Protein During Caloric Restriction in Resistance Trained Lean Athletes: A Case for Higher Intakes. Int J Sport Nutr Exerc Metab. 2013.
7. Lamont LS. A critical review of recommendations to increase dietary protein requirements in the habitually active. Nutr Res Rev. 2012;25(1):142–149. doi:10.1017/S0954422412000030.
8. Tarnopolsky MA, Gibala MJ, Jeukendrup AE, Phillips SM. Nutritional needs of elite endurance athletes. Part II: Dietary protein and the potential role of caffeine and creatine. European Journal of Sport Science. 2005;5(2):59–72. doi:10.1080/17461390500137485.
9. Layman DK. Protein quantity and quality at levels above the RDA improves adult weight loss. J Am Coll Nutr. 2004;23(6 Suppl):631S–636S. Available at: https://pmid.us/15640518.
10. Buchholz AC, Schoeller DA. Is a calorie a calorie? Am J Clin Nutr. 2004;79(5):899S–906S. Available at: https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&id=15113737&retmode=ref&cmd=prlinks.
11. Millward DJ. Macronutrient intakes as determinants of dietary protein and amino acid adequacy. J Nutr. 2004;134(6 Suppl):1588S–1596S. Available at: https://jn.nutrition.org/content/134/6/1588S.long.
12. Munro HN. Energy and protein intakes as determinants of nitrogen balance. Kidney Int. 1978;14(4):313–316. Available at: https://www.nature.com/ki/journal/v14/n4/pdf/ki1978129a.pdf.
13. Edens NK, Gil KM, Elwyn DH. The effects of varying energy and nitrogen intake on nitrogen balance, body composition, and metabolic rate. Clin Chest Med. 1986;7(1):3–17.
14. Rand WM, Pellett PL, Young VR. Meta-analysis of nitrogen balance studies for estimating protein requirements in healthy adults. Am J Clin Nutr. 2003;77(1):109–127. Available at: https://ajcn.nutrition.org/content/77/1/109.full.
15. Evans EM, Mojtahedi MC, Thorpe MP, Valentine RJ, Kris-Etherton PM, Layman DK. Effects of protein intake and gender on body composition changes: a randomized clinical weight loss trial. Nutr Metab (Lond). 2012;9(1):55. doi:10.1186/1743-7075-9-55.
16. Pikosky MA, Smith TJ, Grediagin A, et al. Increased protein maintains nitrogen balance during exercise-induced energy deficit. Med Sci Sports Exerc. 2008;40(3):505–512. doi:10.1249/MSS.0b013e31815f6643.
17. Demling RH, DeSanti L. Effect of a hypocaloric diet, increased protein intake and resistance training on lean mass gains and fat mass loss in overweight police officers. Ann Nutr Metab. 2000;44(1):21–29.
18. Layman DK, Boileau RA, Erickson DJ, et al. A reduced ratio of dietary carbohydrate to protein improves body composition and blood lipid profiles during weight loss in adult women. J Nutr. 2003;133(2):411–417. Available at: https://jn.nutrition.org/content/133/2/411.full.
19. Layman DK, Evans E, Baum JI, Seyler J, Erickson DJ, Boileau RA. Dietary protein and exercise have additive effects on body composition during weight loss in adult women. J Nutr. 2005;135(8):1903–1910. Available at: https://jn.nutrition.org/content/135/8/1903.long.
20. Wycherley TP, Noakes M, Clifton PM, Cleanthous X, Keogh JB, Brinkworth GD. A high-protein diet with resistance exercise training improves weight loss and body composition in overweight and obese patients with type 2 diabetes. Diabetes Care. 2010;33(5):969–976. doi:10.2337/dc09-1974.
21. Mero AA, Huovinen H, Matintupa O, et al. Moderate energy restriction with high protein diet results in healthier outcome in women. J Int Soc Sports Nutr. 2010;7(1):4. doi:10.1186/1550-2783-7-4.
22. Wycherley TP, Moran LJ, Clifton PM, Noakes M, Brinkworth GD. Effects of energy-restricted high-protein, low-fat compared with standard-protein, low-fat diets: a meta-analysis of randomized controlled trials. Am J Clin Nutr. 2012;96(6):1281–1298. doi:10.3945/ajcn.112.044321.
23. Leidy HJ, Carnell NS, Mattes RD, Campbell WW. Higher protein intake preserves lean mass and satiety with weight loss in pre-obese and obese women. Obesity (Silver Spring). 2007;15(2):421–429. doi:10.1038/oby.2007.531.
24. Garthe I, Raastad T, Refsnes PE, Koivisto A, Sundgot-Borgen J. Effect of two different weight-loss rates on body composition and strength and power-related performance in elite athletes. Int J Sport Nutr Exerc Metab. 2011;21(2):97–104.
25. Chaston TB, Dixon JB, O’Brien PE. Changes in fat-free mass during significant weight loss: a systematic review. International Journal of Obesity (2005). 2007;31(5):743–750. Available at: https://www.nature.com/ijo/journal/v31/n5/full/0803483a.html.
26. Bryner RW, Ullrich IH, Sauers J, et al. Effects of resistance vs. aerobic training combined with an 800 calorie liquid diet on lean body mass and resting metabolic rate. J Am Coll Nutr. 1999;18(2):115–121. Available at: https://www.jacn.org/content/18/2/115.long.
27. Mourier A, Bigard AX, de Kerviler E, Roger B, Legrand H, Guezennec CY. Combined effects of caloric restriction and branched-chain amino acid supplementation on body composition and exercise performance in elite wrestlers. Int J Sports Med. 1997;18(1):47–55. doi:10.1055/s-2007-972594.
28. Mettler S, Mitchell N, Tipton KD. Increased protein intake reduces lean body mass loss during weight loss in athletes. Med Sci Sports Exerc. 2010;42(2):326–337. doi:10.1249/MSS.0b013e3181b2ef8e.
29. Campbell B, Kreider RB, Ziegenfuss T, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr. 2007;4:8. doi:10.1186/1550-2783-4-8.
30. Rodriguez NR, Di Marco NM, Langley S. American College of Sports Medicine position stand. Nutrition and athletic performance. Med Sci Sports Exerc. 2009;41(3):709–731. Available at: https://www.scandpg.org/local/resources/files/2010/PP_NutritionAthleticPerformance.pdf.