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How much protein is too much?
For healthy adults, no upper limit for protein has been set; the official guidance only says protein should be 10–35% of your calories. High-protein diets (1.5 g/kg or more) didn't change kidney function in healthy adults in a 2018 review of 28 studies. The real limits are practical: protein crowding out vegetables, fibre and carbs you need for training. If you have kidney disease, it's different: protein is often restricted, and your doctor or dietitian sets the amount.
What the guidelines say
The US Dietary Reference Intakes set a minimum (the RDA, 0.8 g/kg) and an acceptable range of 10–35% of calories from protein, but no tolerable upper limit, because no clear harm has been found in healthy people. At 2,000 calories, 35% is 175 g of protein a day.
Is high protein bad for your kidneys?
Not for healthy kidneys. A 2018 meta-analysis of 28 studies (1,358 people) compared higher-protein diets (at least 1.5 g/kg, 20% of calories or 100 g a day) with normal ones: kidney filtration rose slightly but the change over time didn't differ. The studies were mostly short and didn't include people with kidney disease. For people with chronic kidney disease (stages 3–5, not on dialysis), guidelines restrict protein to about 0.55–0.6 g/kg of ideal weight; with diabetes 0.6–0.8 g/kg. If you have reduced kidney function, diabetes with kidney problems, or a single kidney, ask before going high.
Signs you're overdoing protein
- Few vegetables, fruit and whole grains, and constipation from too little fibre.
- Low energy in hard training because carbs are squeezed out.
- Thirst: breaking down protein makes more waste to flush out, so drink enough water.
- Spending a lot on supplements you don't need.
How much is "high"?
| Level | g/kg | Grams a day |
|---|---|---|
| Minimum (RDA) | 0.8 | 60 g |
| Active adult | 1.2–1.6 | 90 g–120 g |
| Lifting, dieting | 1.6–2.2 | 120 g–165 g |
| Very high | 3.0+ | 225 g+ |
Above about 2.2 g/kg there's little extra benefit for muscle for most people, so more protein mostly replaces other food. Your useful target is in the protein calculator; the right balance with carbs and fat is in the macro calculator.
Is 2 eggs a day too much protein?
No: two large eggs have about 13 g of protein, a fraction of what most adults need. The same goes for one protein shake a day (20–25 g). See how much protein a day.
Sources
- Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press, 2005 (RDA 0.8 g/kg; AMDR 10–35% of energy; no upper limit set).
- 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. J Nutr 2018;148(11):1760–1775.
- Ikizler TA, Burrowes JD, Byham-Gray LD, et al. KDOQI clinical practice guideline for nutrition in CKD: 2020 update. Am J Kidney Dis 2020;76(3 Suppl 1):S1–S107.
- U.S. Department of Agriculture, Agricultural Research Service. FoodData Central, SR Legacy (2018). Food IDs in the table notes.