How Much Protein Do You Need Per Day? The Science-Backed Answer by Goal and Body Weight
Protein is the most important macronutrient for body composition, whether you want to build muscle, lose fat, or simply maintain your health as you age. But the question everyone asks is: how much do I actually need? The answer depends on your body weight, your goals, and your activity level.
The Basics: Why Protein Matters
Protein is made up of amino acids, which are the building blocks your body uses to repair muscle tissue, produce enzymes and hormones, support immune function, and maintain healthy skin, hair, and nails. Unlike fat and carbohydrates, your body does not store excess protein efficiently, so you need a consistent daily intake.
There are 20 amino acids in total. Nine of them are "essential," meaning your body cannot make them and must get them from food. This is why protein quality matters, not just quantity.
The RDA: A Minimum, Not a Target
The Recommended Dietary Allowance (RDA) for protein is 0.8 grams per kilogram of body weight per day (about 0.36g per pound). For a 70 kg (154 lb) person, that is just 56 grams per day. However, this number represents the minimum needed to prevent deficiency in sedentary individuals. It is not the optimal amount for health, fitness, or body composition.
Research consistently shows that higher protein intakes benefit almost everyone, from athletes to older adults trying to prevent muscle loss.
Protein Needs by Goal
Here is what the current research recommends based on your primary goal:
| Goal | Protein (g/kg body weight) | For 70 kg / 154 lb person | For 90 kg / 198 lb person |
|---|---|---|---|
| Sedentary maintenance | 0.8-1.0 g/kg | 56-70 g/day | 72-90 g/day |
| Active maintenance | 1.0-1.2 g/kg | 70-84 g/day | 90-108 g/day |
| Weight loss (preserve muscle) | 1.2-1.6 g/kg | 84-112 g/day | 108-144 g/day |
| Muscle building | 1.6-2.2 g/kg | 112-154 g/day | 144-198 g/day |
| Endurance athletes | 1.2-1.6 g/kg | 84-112 g/day | 108-144 g/day |
| Strength athletes | 1.6-2.4 g/kg | 112-168 g/day | 144-216 g/day |
Use our protein calculator to get a personalized recommendation based on your exact weight and goals.
Why Higher Protein for Weight Loss?
When you eat in a calorie deficit, your body breaks down both fat and muscle for energy. Higher protein intake (1.2-1.6 g/kg) helps preserve lean muscle mass during weight loss. Studies show that people on high-protein diets lose more fat and less muscle compared to those on standard protein diets, even at the same calorie deficit. Protein also increases satiety, helping you feel full longer and making it easier to stick to your diet.
The Muscle Building Sweet Spot
A landmark 2018 meta-analysis published in the British Journal of Sports Medicine analyzed 49 studies and found that protein intake of 1.6 g/kg per day maximized muscle gains from resistance training. Going above 2.2 g/kg showed no additional benefit for most people. So if you are lifting weights and want to build muscle, aim for 1.6-2.2 g/kg as your target range.
Age Matters: Older Adults Need More
As you age, your body becomes less efficient at using dietary protein to build muscle, a phenomenon called "anabolic resistance." Adults over 50 should aim for 1.2-1.6 g/kg per day to prevent sarcopenia (age-related muscle loss). This is significantly higher than the standard RDA of 0.8 g/kg, which many experts consider inadequate for older populations.
Protein Quality: Complete vs. Incomplete
Not all protein sources are equal. "Complete" proteins contain all nine essential amino acids in adequate amounts. Animal proteins (meat, fish, eggs, dairy) are all complete. Most plant proteins are "incomplete," lacking one or more essential amino acids. However, you can combine plant sources throughout the day (rice + beans, hummus + pita) to get all essential amino acids.
The key amino acid for muscle building is leucine, which triggers muscle protein synthesis. You need about 2-3 grams of leucine per meal to maximize this response. Animal proteins are naturally rich in leucine, while plant proteins require larger servings to hit this threshold.
Best Protein Sources
| Food | Protein per Serving | Serving Size | Complete? |
|---|---|---|---|
| Chicken breast | 31 g | 100 g (3.5 oz) | Yes |
| Salmon | 25 g | 100 g (3.5 oz) | Yes |
| Greek yogurt | 17 g | 1 cup (245 g) | Yes |
| Lentils (cooked) | 18 g | 1 cup (198 g) | No |
| Cottage cheese | 14 g | 1/2 cup (113 g) | Yes |
| Eggs | 6 g | 1 large egg | Yes |
| Tofu (firm) | 8 g | 100 g (3.5 oz) | Yes |
| Black beans (cooked) | 15 g | 1 cup (172 g) | No |
| Whey protein powder | 25 g | 1 scoop (30 g) | Yes |
Protein Timing: Does It Matter?
The idea of an "anabolic window" (needing protein within 30 minutes of a workout) has been largely debunked. Current research suggests that total daily protein intake matters far more than precise timing. That said, distributing your protein across 3-4 meals (25-40 g per meal) is more effective than eating most of it in one sitting. Your body can only use so much protein for muscle synthesis at once, so spreading it out gives you more "muscle-building events" throughout the day.
Can You Eat Too Much Protein?
For healthy individuals, high protein diets (up to 2.2-3.0 g/kg) have been studied extensively and show no negative effects on kidney function, bone health, or liver function. However, if you have pre-existing kidney disease, consult your doctor before significantly increasing protein intake. For most people, the practical upper limit is about how much protein you can eat while still getting enough fats and carbohydrates for energy and overall health.
Ready to find your exact number? Use our protein calculator to get a personalized daily target.
Frequently Asked Questions
Is 100 grams of protein per day enough?
It depends on your body weight and goals. For a 70 kg (154 lb) person doing general fitness, 100 g (1.4 g/kg) is solid for most goals. For a 90 kg person trying to build muscle, 100 g (1.1 g/kg) would be on the low side. Use the table above or our protein calculator to find your personal target.
Do I need protein supplements?
No. Protein supplements (whey, casein, plant-based powders) are convenient but not necessary. Whole foods provide the same amino acids plus additional nutrients like vitamins, minerals, and fiber. Supplements are useful when you struggle to hit your target through food alone, or need a quick post-workout option.
Can I get enough protein on a vegan diet?
Yes, but it requires more planning. Good plant-based protein sources include lentils, chickpeas, tofu, tempeh, seitan, edamame, and quinoa. Combine different sources throughout the day to get all essential amino acids. You may need to eat slightly more total protein (add 10-20%) since plant proteins have lower digestibility than animal proteins.
Does cooking affect protein content?
Cooking does not significantly reduce the protein content of foods. In fact, cooking often makes protein more digestible and bioavailable. The protein values listed on nutrition labels account for the cooked state of the food when applicable. You do not need to worry about "losing protein" through cooking.
Should I eat protein before or after a workout?
Both work. The most important factor is getting adequate protein throughout the day. If you train fasted in the morning, having protein within a couple of hours after your workout is beneficial. If you had a protein-rich meal 2-3 hours before training, the timing of your post-workout protein is less critical. Focus on consistency over precision.