How Much Protein Do You Need Per Day? (Calculator + Guide)

The Short Answer: It Depends on Your Goals

The amount of protein you need per day varies significantly depending on your body weight, activity level, age, and goals. The minimum recommended by government guidelines is far less than what most active people actually need for optimal results.

Here's a quick summary of the science-backed ranges before we dive into the details:

• Sedentary adults: 0.8 g/kg body weight/day (the RDA minimum)
• Active adults and regular exercisers: 1.2-1.6 g/kg/day
• Strength training for muscle growth: 1.6-2.2 g/kg/day
• During a calorie deficit (fat loss): 1.6-2.4 g/kg/day
• Older adults (65+): 1.0-1.2 g/kg/day minimum

Not sure where you fall? Use our free macro calculator to get a personalized protein target based on your body stats and goals.

The RDA: Why 0.8 g/kg Is the Floor, Not the Target

The U.S. Institute of Medicine's Dietary Reference Intakes set the Recommended Dietary Allowance (RDA) for protein at 0.8 grams per kilogram of body weight per day for adults. The World Health Organization adopted the same figure in 2007.

For a 70 kg (154 lb) person, that's just 56 grams of protein per day — roughly one chicken breast and a cup of Greek yogurt. That might sound low, and it is. The RDA represents the minimum amount needed to prevent deficiency in most healthy adults, not the amount needed to optimize body composition, performance, or recovery.

As researchers noted in a 2023 review published in Advances in Nutrition, there is growing evidence that the current RDA may be insufficient for optimal health outcomes, particularly for active individuals and older adults.

How Much Protein for Muscle Growth

If you're doing resistance training and want to build muscle, you need significantly more protein than the RDA. A landmark 2018 meta-analysis by Morton et al. analyzed 49 studies with 1,863 participants and found that protein supplementation significantly increased muscle mass and strength gains during resistance training, with benefits plateauing at approximately 1.6 g/kg/day.

However, the confidence interval in that study was broad (1.03-2.20 g/kg/day), which is why most sports nutrition experts recommend a range of 1.6 to 2.2 g/kg/day for people doing regular resistance training. For a 80 kg (176 lb) person, that's 128 to 176 grams of protein per day.

The practical takeaway: if you lift weights and want to maximize muscle growth, aim for at least 1.6 g/kg/day. Going up to 2.2 g/kg provides a safety margin and may offer small additional benefits, especially if your training volume is high.

How Much Protein for Weight Loss

Protein becomes even more important when you're in a calorie deficit for weight loss. Without adequate protein, your body will break down muscle tissue along with fat — which slows your metabolism and leads to a "skinny fat" outcome.

A review published in the International Journal of Sport Nutrition and Exercise Metabolism recommends 1.6 to 2.4 g/kg/day during a calorie deficit to preserve lean mass. The more aggressive your deficit and the leaner you already are, the higher your protein needs.

A 2016 randomized trial in the American Journal of Clinical Nutrition demonstrated this dramatically: participants consuming 2.4 g/kg/day during a 40% energy deficit actually gained lean body mass while losing fat. Those eating 1.2 g/kg/day lost both muscle and fat.

Beyond muscle preservation, protein helps with weight loss in two other ways. First, protein has the highest thermic effect of any macronutrient — your body uses 20-30% of protein's calories just to digest it, compared to 5-10% for carbs and 0-3% for fat. Second, a meta-analysis in the Journal of the Academy of Nutrition and Dietetics confirmed that higher protein intake increases feelings of fullness compared to lower-protein meals, helping you eat less without constant hunger.

How Much Protein for Older Adults

As you age, your body becomes less efficient at using protein to build and maintain muscle — a process called anabolic resistance. This contributes to age-related muscle loss (sarcopenia), which affects strength, mobility, and overall health.

The PROT-AGE Study Group, an international expert panel, recommends that adults over 65 consume at least 1.0 to 1.2 g/kg/day of protein to maintain muscle mass and function. For older adults with acute or chronic illnesses, they recommend 1.2 to 1.5 g/kg/day.

This is 25-50% more than the standard RDA of 0.8 g/kg. If you're over 65, increasing your protein intake is one of the most impactful things you can do for maintaining strength and independence.

Protein by Body Weight: Quick Reference

All values are calculated directly from the research-backed ranges. For a personalized target that accounts for your age, activity, and goals, use our macro calculator.

Best Protein Sources

Not all protein sources are equal. Here are the most protein-dense whole foods based on USDA FoodData Central data:

• Chicken breast (cooked, skinless): ~31 g protein per 100 g
• Greek yogurt (nonfat): ~10 g protein per 100 g
• Eggs: ~13 g protein per 100 g (about 6 g per large egg)
• Salmon (cooked): ~25 g protein per 100 g
• Lean ground beef (90/10, cooked): ~26 g protein per 100 g
• Cottage cheese (low-fat): ~12 g protein per 100 g
• Tofu (firm): ~17 g protein per 100 g
• Lentils (cooked): ~9 g protein per 100 g
• Whey protein powder: ~25 g protein per scoop (varies by brand)

A mix of animal and plant sources works best for most people. Plant-based eaters can hit high protein targets by combining legumes, tofu, tempeh, seitan, and protein supplements.

Is Too Much Protein Bad for Your Kidneys?

This is one of the most common concerns about high-protein diets. A 2018 systematic review and meta-analysis analyzing 28 studies with 1,358 participants found that higher protein intakes did not adversely affect kidney function (measured by glomerular filtration rate) in healthy adults.

However, if you have pre-existing kidney disease, you should consult your doctor before significantly increasing protein intake. The research on safety specifically applies to people with healthy kidneys, and most studies were limited to 6 months or less in duration.

How to Hit Your Protein Target Every Day

• Spread protein across meals. Aim for 25-40 g of protein per meal rather than cramming it all into dinner. This helps maximize muscle protein synthesis throughout the day.
• Build every meal around a protein source. Choose your protein first (chicken, fish, eggs, tofu, etc.), then add carbs and fat around it. This ensures protein doesn't become an afterthought.
• Use a tracker. Most people overestimate their protein intake. An AI tracker like MacroChat makes it easy to see exactly where you stand — just say or type what you ate.
• Keep high-protein snacks on hand. Greek yogurt, jerky, cottage cheese, hard-boiled eggs, and protein bars are convenient options to fill gaps between meals.
• Supplement strategically. A protein shake (whey, casein, or plant-based) is an efficient way to add 25-30 g when you can't hit your target through whole foods alone.

Frequently Asked Questions

How much protein per day for a 150 lb person?

A 150 lb (68 kg) person needs 54 g/day at the RDA minimum. For active individuals: 82-109 g/day. For muscle building or fat loss: 109-150 g/day. The right target depends on your goals and activity level.

Do you need protein on rest days?

Yes. Muscle repair and growth continue for 24-48 hours after a workout. Cutting protein on rest days undermines recovery. Keep protein consistent every day, regardless of whether you trained.

Can you eat too much protein in one sitting?

Your body can digest and use protein from large meals, but distributing protein across 3-5 meals per day (25-40 g each) is likely more effective for maximizing muscle protein synthesis than eating it all at once.

What's the best time to eat protein?

Total daily intake matters more than timing. That said, having protein within a few hours of your workout (before or after) and spreading intake evenly across meals is a solid approach.

Get Your Personalized Protein Target

The right protein intake depends on your weight, goals, and activity level. Rather than guessing, calculate your exact target.

Use our free macro calculator to get your personalized protein, carb, and fat targets in seconds. Or try MacroChat free for 3 days to track your protein intake effortlessly — just say, type, or snap a photo of what you ate.

Sources

• Institute of Medicine. "Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids." The National Academies Press, 2005. Read reference tables
• Hudson JL, et al. "Is It Time to Reconsider the U.S. Recommendations for Dietary Protein and Amino Acid Intake?" Advances in Nutrition, 2023. Read study
• Morton RW, 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." British Journal of Sports Medicine, 2018. Read study
• Hector AJ, Phillips SM. "Protein Recommendations for Weight Loss in Elite Athletes." International Journal of Sport Nutrition and Exercise Metabolism, 2018. Read study
• Longland TM, et al. "Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss." American Journal of Clinical Nutrition, 2016. Read study
• Bauer J, et al. "Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group." Journal of the American Medical Directors Association, 2013. Read study
• Devries MC, 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." Journal of Nutrition, 2018. Read study
• Calcagno M, et al. "The Thermic Effect of Food: A Review." Journal of the American College of Nutrition, 2019. Read study
• Dhillon J, 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. Read study
• USDA. "FoodData Central." View database