MVIIIHealth The MVIII app
← Back

Research · Diets

High-protein diet

In weight-loss trials, higher-protein diets kept about 0.3 to 0.4 kg more lean mass and removed slightly more fat than standard-protein diets. Fullness rose after high-protein meals in lab studies. Kidney filtration rose in people without kidney disease, with no consistent sign of injury in short trials. A cohort linked more protein to faster decline in mild kidney impairment.

Add to Bio HackChecked 2026-11-13
Status
A dietary pattern, not a regulated product.
Also called
high protein diet, higher-protein diet, protein-rich diet, high-protein weight-loss diet, high-protein low-carbohydrate diet, protein diet
Followed for
weight loss, fat loss, keeping muscle while dieting, fullness, appetite control, blood sugar, type 2 diabetes

Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on

Shown to help4

Reported risks3

What people follow it for, and what was found

Shown to help4

Strong

Lean mass during weight loss

Shown to keep about 0.3 to 0.4 kg more lean mass during calorie-restricted weight loss than standard-protein diets, including in adults over 50.

Compared with diets with less protein

The numbers and sources
Effect
Energy-restricted high-protein diets reduced the loss of fat-free mass by 0.43 kg (95% CI 0.09 to 0.78) and of resting energy expenditure by 595.5 kJ a day against standard-protein diets [1]. Protein above the RDA reduced lean mass loss during energy restriction by 0.36 kg (95% CI 0.06 to 0.67, 14 comparisons) and added 0.77 kg with resistance training (95% CI 0.23 to 1.31), with no effect when people neither dieted nor trained (0.08 kg, 95% CI -0.59 to 0.75) [2]. In a network meta-analysis of 83 articles, high-protein diets raised lean body mass 0.34 kg against normal-protein diets (95% CI 0.11 to 0.57) [3]. In adults over 50, higher protein during weight loss kept more lean mass and lost more fat [4].
Population
1,063 adults in 24 trials lasting a mean of 12.1 weeks [1]; healthy adults in 18 trials of at least 6 weeks [2]; adults in randomized trials [3]; adults over 50 in 20 RCTs [4].
Sources
[1], [2], [3], [4]
Caveats
A 2026 review of 22 trials in adults without kidney disease found no significant change in fat-free mass [5]. The abstract of [4] gives no effect sizes.
Strong

Fat loss and body weight

Shown to lower body weight and fat mass slightly more than standard-protein diets, by about 0.6 to 0.9 kg of fat.

Compared with diets with less protein

The numbers and sources
Effect
On isocaloric energy-restricted diets, high protein lowered weight 0.79 kg more (95% CI 0.08 to 1.50) and fat mass 0.87 kg more (95% CI 0.48 to 1.26) [1]. Across 74 trials, higher-protein diets favored weight loss (SMD -0.36, 95% CI -0.56 to -0.17) and waist circumference (SMD -0.43, 95% CI -0.69 to -0.16) [6]. Fat mass fell 0.64 kg more (95% CI 0.29 to 0.98) [3]. In adults without kidney disease, high-protein diets lowered body fat percentage and total fat mass [5].
Population
Adults in weight-loss trials [1][3]; 74 trials of higher against lower protein [6]; 22 RCTs in adults without chronic kidney disease [5].
Sources
[1], [3], [5], [6]
Caveats
The differences are under 1 kg [1][3]. Most trials were short, a mean of 12.1 weeks in [1].
Moderate

Fullness

Shown to raise fullness ratings after higher-protein meals in tightly controlled preload studies of healthy adults.

Compared with diets with less protein

The numbers and sources
Effect
In 5 preload studies, higher-protein preloads raised fullness over 2 to 4 hours more than lower-protein preloads (2,435.74 mm·240 min, 95% CI 1,375.18 to 3,496.31). A directional count of 28 studies also favored higher protein [7]. In weight-loss trials, 3 of 5 studies reported greater satiety with high protein [1].
Population
Healthy adults given intact protein by mouth [7]; adults in weight-loss trials [1].
Sources
[1], [7]
Caveats
The authors caution against extending these results to everyday eating, body weight or health outcomes [7].
Moderate

HbA1c in type 2 diabetes

Shown to lower HbA1c about 0.5% more than standard-protein diets within 6 months in type 2 diabetes, in one meta-analysis of nine small trials.

Compared with diets with less protein

The numbers and sources
Effect
Against diets with 15% to 20% of energy from protein, diets with 25% to 32% lowered weight 2.08 kg more (95% CI 0.90 to 3.25) and HbA1c 0.52% more (95% CI 0.14 to 0.90). Fasting glucose and blood lipids did not differ [8].
Population
418 adults with type 2 diabetes in 9 trials lasting 4 to 24 weeks [8].
Sources
[8]
Caveats
Two studies had a large influence on the weight and HbA1c results [8]. The indexed abstract prints minus signs as the digit 2. The figures here follow its text, which reports reductions.

Mixed results1

Moderate

Blood pressure and triglycerides

Mixed results: triglycerides fell more on higher-protein diets in two meta-analyses, while blood pressure fell slightly in one and did not differ in another.

Compared with diets with less protein

The numbers and sources
Effect
Across 74 trials, higher-protein diets lowered systolic (SMD -0.21, 95% CI -0.32 to -0.09) and diastolic blood pressure (SMD -0.18, 95% CI -0.29 to -0.06) and triglycerides (SMD -0.51, 95% CI -0.78 to -0.24). Total and LDL cholesterol, C-reactive protein and HbA1c did not change [6]. In energy-restricted trials, triglycerides fell 0.23 mmol/L more (95% CI 0.12 to 0.33), and blood pressure and total, LDL and HDL cholesterol did not differ [1].
Population
Adults in 74 trials [6] and in 24 weight-loss trials [1].
Sources
[1], [6]
Caveats
Restricting to studies at lower risk of bias reduced the triglyceride effect [6]. In type 2 diabetes, blood pressure changes were not significant [8].

How trials defined it

Trials defined high protein in several ways: 25% to 35% of energy or at least 2.0 g per kg a day [5]; at least 1.5 g per kg a day, at least 20% of energy or at least 100 g a day [9]; at least 25% of energy or 1.0 g per kg a day in adults over 50 [4]; and any intake above the RDA of 0.8 g per kg a day [2]. Weight-loss trials matched calories and fat and swapped carbohydrate for protein, for a mean of 12.1 weeks [1]. Diabetes trials compared 25% to 32% of energy from protein with 15% to 20%, for 4 to 24 weeks [8]. In a 12-month trial in type 2 diabetes with early kidney disease, the moderate-protein diet averaged 19 g a day more protein than the standard diet [10].

Risks

Reported risks2

StrongHow often is not known

Kidney function in people without kidney disease

Shown to raise kidney filtration rate, urea and urine calcium in people without kidney disease, with no consistent sign of kidney injury in mostly short trials.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Across 30 studies (2,160 people), GFR rose 7.18 mL/min/1.73 m² more on high-protein diets (95% CI 4.45 to 9.91), with higher serum urea (1.75 mmol/L), urinary calcium (25.43 mg a day) and serum uric acid [11]. In 22 RCTs, eGFR rose (SMD 0.39, 95% CI 0.09 to 0.69, I² 74.9%) and serum creatinine did not change (SMD 0.08, 95% CI -0.09 to 0.25) [5]. In 28 trials (1,358 people), GFR after the diet was slightly higher (SMD 0.19, 95% CI 0.07 to 0.31), and the change in GFR did not differ (SMD 0.11, 95% CI -0.05 to 0.27) [9].
Population
Adults without chronic kidney disease in randomized trials [5][9][11].
Sources
[5], [9], [11]
Caveats
Most trials were short and used creatinine-based estimates, so long-term effects are uncertain [5]. Cohorts disagree: in 9,226 Korean adults, the highest protein quarter was linked to 1.32 times the risk of rapid eGFR decline (95% CI 1.02 to 1.73) [12], while a meta-analysis of 6 cohorts (148,051 people) linked higher protein to lower chronic kidney disease incidence (RR 0.82, 95% CI 0.71 to 0.94) [13].
ModerateHow often is not known

Digestive side effects

Shown to cause more gastrointestinal adverse events than lower-protein diets across trials.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Adverse gastrointestinal events were more common with high-protein diets in a meta-analysis of 74 trials [6].
Population
Adults in 74 trials of higher against lower protein [6].
Sources
[6]
Caveats
The abstract does not give rates or say which events [6].

Mixed results1

LimitedHow often is not known

Kidney function in people with kidney disease

Mixed results: two trials including people with early kidney disease found no harm to kidney function, while a cohort linked more protein to faster decline in women with mild impairment.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
In type 2 diabetes with early kidney disease, 12 months on a moderate-protein against a standard-protein weight-loss diet did not change isotope-measured GFR, eGFR, cystatin C or albuminuria. Weight loss improved kidney function on both [10]. In a 2-year trial, eGFR rose similarly on low-carbohydrate (protein 22% of energy), Mediterranean and low-fat diets, and rose 7.1% in people starting with eGFR under 60 [14]. Over 11 years, each 10 g a day more protein was linked to an eGFR change of -1.69 mL/min/1.73 m² (95% CI -2.93 to -0.45) in women with mild renal insufficiency, and to no change in women with normal function [15].
Population
76 adults with type 2 diabetes and an albumin to creatinine ratio of 3 to 30 mg/mmol, 45 completing [10]; 318 adults with eGFR of 30 or more, 86% men [14]; 1,624 women aged 42 to 68 in the Nurses' Health Study, observational [15].
Sources
[10], [14], [15]
Caveats
The trials were small or not designed around kidney disease, and the protein difference was modest, 19 g a day in [10]. The cohort used food questionnaires, and the link was strongest for nondairy animal protein [15].

Claims tested and not found

  1. That high-protein diets damage the kidneys in healthy adults. The change in GFR did not differ from lower-protein diets [9], and serum creatinine did not change [5].
  2. That extra protein adds lean mass without dieting or training. Without energy restriction or resistance training, lean mass did not differ (0.08 kg, 95% CI -0.59 to 0.75) [2].

Sources

  1. Wycherley TP, Moran LJ, Clifton PM, et al. Effects of energy-restricted high-protein, low-fat compared with standard-protein, low-fat diets: a meta-analysis of randomized controlled trials. The American Journal of Clinical Nutrition. 2012. https://doi.org/10.3945/ajcn.112.044321
  2. Hudson JL, Wang Y, Bergia RE, et al. Protein Intake Greater than the RDA Differentially Influences Whole-Body Lean Mass Responses to Purposeful Catabolic and Anabolic Stressors: A Systematic Review and Meta-analysis. Advances in Nutrition. 2020. https://doi.org/10.1093/advances/nmz106
  3. Yao Y, Lin S, He Z, et al. Impact of other macronutrient composition within high-protein diet on body composition and cardiometabolic health: a systematic review, pairwise, and network meta-analysis of randomized controlled trials. International Journal of Obesity. 2025. https://doi.org/10.1038/s41366-025-01806-5
  4. Kim JE, O'Connor LE, Sands LP, et al. Effects of dietary protein intake on body composition changes after weight loss in older adults: a systematic review and meta-analysis. Nutrition Reviews. 2016. https://doi.org/10.1093/nutrit/nuv065
  5. Teixeira Silva PR, Santos P, de Miranda Silva Nogueira PA, et al. Effects of High-Protein Diets on Renal Function and Body Composition in Adults Without Chronic Kidney Disease: A Systematic Review and Meta-Analysis of Randomised Trials. Diabetes, Obesity and Metabolism. 2026. https://doi.org/10.1111/dom.70996
  6. Santesso N, Akl EA, Bianchi M, et al. Effects of higher- versus lower-protein diets on health outcomes: a systematic review and meta-analysis. European Journal of Clinical Nutrition. 2012. https://doi.org/10.1038/ejcn.2012.37
  7. Dhillon J, Craig BA, Leidy HJ, et al. The Effects of Increased Protein Intake on Fullness: A Meta-Analysis and Its Limitations. Journal of the Academy of Nutrition and Dietetics. 2016. https://doi.org/10.1016/j.jand.2016.01.003
  8. Dong JY, Zhang ZL, Wang PY, et al. Effects of high-protein diets on body weight, glycaemic control, blood lipids and blood pressure in type 2 diabetes: meta-analysis of randomised controlled trials. British Journal of Nutrition. 2013. https://doi.org/10.1017/s0007114513002055
  9. Devries MC, Sithamparapillai A, Brimble KS, et al. Changes in Kidney Function Do Not Differ between Healthy Adults Consuming Higher- Compared with Lower- or Normal-Protein Diets: A Systematic Review and Meta-Analysis. The Journal of Nutrition. 2018. https://doi.org/10.1093/jn/nxy197
  10. Jesudason DR, Pedersen E, Clifton PM. Weight-loss diets in people with type 2 diabetes and renal disease: a randomized controlled trial of the effect of different dietary protein amounts. The American Journal of Clinical Nutrition. 2013. https://doi.org/10.3945/ajcn.113.060889
  11. Schwingshackl L, Hoffmann G. Comparison of high vs. normal/low protein diets on renal function in subjects without chronic kidney disease: a systematic review and meta-analysis. PLoS ONE. 2014. https://doi.org/10.1371/journal.pone.0097656
  12. Jhee JH, Kee YK, Park S, et al. High-protein diet with renal hyperfiltration is associated with rapid decline rate of renal function: a community-based prospective cohort study. Nephrology Dialysis Transplantation. 2019. https://doi.org/10.1093/ndt/gfz115
  13. Cheng Y, Zheng G, Song Z, et al. Association between dietary protein intake and risk of chronic kidney disease: a systematic review and meta-analysis. Frontiers in Nutrition. 2024. https://doi.org/10.3389/fnut.2024.1408424
  14. Tirosh A, Golan R, Harman-Boehm I, et al. Renal function following three distinct weight loss dietary strategies during 2 years of a randomized controlled trial. Diabetes Care. 2013. https://doi.org/10.2337/dc12-1846
  15. Knight EL, Stampfer MJ, Hankinson SE, et al. The impact of protein intake on renal function decline in women with normal renal function or mild renal insufficiency. Annals of Internal Medicine. 2003. https://doi.org/10.7326/0003-4819-138-6-200303180-00009

Everything in the library