Adults generally need 0.8 grams (g) per kilogram (kg) of body weight (0.36g per pound) per day. Still, how much protein you should eat per day you need depends on factors like your activity levels, age, size, and weight. Your goals also influence your protein intake. For example, you will generally need more protein than average to gain muscle or to lose weight.
You can use some simple rules of thumb to meet your protein goals. Read on to find out how much protein you need to eat per day, depending on different goals and other factors.
1. What Are the Benefits of Protein?
Every cell in your body needs protein to work properly. Protein helps support healthy growth and development in children, adolescents, and pregnant people.
Other benefits of protein include:
- Aids in blood clotting
- Builds muscle mass and strength and helps your muscles contract
- Creates and repairs cells
- Fights infections
- Helps maintain balance of bodily fluids
- Transfers fats, minerals, oxygen, and vitamins throughout your body
2. How Much Protein Should I Eat per Day?
Trying to get enough protein per day is important. Your body does not store protein the way it does fats and carbs. The Recommended Dietary Allowance (RDA) is the minimum amount needed for 97% to 98% of people your age and sex to be healthy.
Here's a look at the general RDA guidelines for protein, depending on age and sex:
Age | Female | Male |
---|---|---|
1–3 years | 13g | 13g |
4–8 years | 19g | 19g |
9–13 years | 34g | 34g |
14–18 years | 46g | 52g |
19 years and older | 46g | 56g |
Of note: The RDA has not been updated since 2011 and does not consider factors like your activity level or weight loss goals. You may need more or less protein than the general RDA guidelines, depending on those factors.
3. How Much Should I Eat To Gain Muscle?
You'll need more protein than the general RDA guidelines to build muscle with resistance training. A study published in 2022 found that 1.5g per kg (0.68g per pound) is optimal for building or maintaining muscle. For example, a 150-pound person would need to consume 102g of protein per day. More protein than that does not reap further rewards.
Upping your protein intake can help you make gains regardless of your age, weight, height, and other factors as long as you are resistance training. The study also found that you do not gain muscle by simply adding extra protein to your diet.
4. How Much Protein Should I Eat To Lose Weight?
Protein has a higher thermic effect than carbs and fat. In other words, your body uses more calories from protein to digest and metabolize your food. As a result, research has shown that a high-protein diet boosts metabolism and helps you burn fat.
"When you bring protein to about 30% of your daily calories, you'll naturally eat less," Lauren Slayton, RDN, founder of Foodtrainers and author "The Little Book of Thin," told Health. Protein takes longer to digest than carbs, helps you feel full, and pushes your body to secrete the gut hormone peptide YY, which reduces hunger.
5. How Much Protein After Exercise?
Active people get at least 30 minutes of moderate-intensity exercise per day, five days per week, and do resistance training twice per week. Consider eating 1.2g to 2g of protein per kg (or about 0.5g to 0.9g per pound) if you are active, Nancy Rodriguez, PhD, RDN, a faculty member at the University of Connecticut, told Health. Some evidence suggests that amount helps rebuild muscle tissue, especially if you do a lot of high-intensity workouts.
6. How Much Protein Is Too Much?
Many people consume more protein than the general RDA guidelines. Most Americans consume more than 15% of their calories from protein, which amounts to 75g for a 2,000-calorie diet. It's possible to consume too much protein, which may be unsafe.
Eating more than 35% of your calories from protein might increase your risk of:
- Bone and calcium homeostasis disorders
- Cancer
- Liver disease
- Renal (kidney) disease
A high-protein diet might negatively affect liver and kidney function, although results are mixed. A study published in 2016 found that men who ate 2.51g to 3.32g of protein per kg (1.14g to 1.51g per pound) per day and did resistance training for one year did not have impaired liver or kidney function. It might help to talk to a healthcare provider about how much protein is best for you if you are unsure.
7. What Happens if You Don’t Enough Protein?
Although rare, you might develop kwashiorkor, or a protein deficiency, if you do not consume as much protein as your body needs. Kwashiorkor symptoms include:
- Abdominal extension
- Changes in hair color and texture
- Diarrhea
- Failure to thrive (in infants)
- Fatigue
- Irritability
- Loss of muscle mass
- Skin pigment changes
- Swelling
- Weakened immune system, resulting in more frequent infections
8. What Are the Best Sources of Protein?
Many animal foods are sources of protein, but you can consume plenty of protein on a vegetarian or vegan diet. There are plenty of plant-based protein sources.
Here are some of the best sources of protein:
- Eggs
- Fish
- Legumes
- Low-fat and fat-free dairy products (e.g., cheese, milk, and yogurt)
- Meat and poultry (e.g., chicken, lean beef, and turkey)
- Nuts and seeds
Other Factors
Several factors affect your protein intake, in addition to your age, activity level, goals, size, and weight. You might need to adjust your protein intake if you:
- Are breastfeeding: You must consume more protein than average to help maintain your muscle mass and provide nutrient-rich breast milk. Research has shown that breastfeeding females who are within six months postpartum need 1.06g of protein per kg (0.48g per pound).
- Are older than 70: About half of females and 30% of males older than 70 get less protein than they need. It might be helpful for people in this age group to bump up their consumption of beans, peas, lentils, seafood, dairy, and fortified soy products.
- Are pregnant: Pregnant people need more protein than usual to help support fetal development. You'll need 0.8g per kg (0.36g per pound) during the first trimester and 1.1g per kg (0.50g per pound) during the second and third trimesters.
- Have sarcopenia: This is the natural loss of muscle that happens with age. Research has found that 1.2g to 1.6g per kg (0.55g to 0.7g per pound) is optimal for maintaining muscle. That's roughly 83–105 grams per day for a 150-pound person.
A Quick Review
Protein helps build muscle mass and strength and creates and repairs cells. The general RDA guideline for protein is about 0.36g per pound for adults. That amounts to about 54g per day for a 150-pound person. Many Americans typically get more than 15% of their calories from protein, so you may already be getting enough.
You might need more protein, depending on several factors. For example, people who are active, trying to build muscle, or working to lose weight will need about 0.5g to 0.9g of protein per pound. That's about 75–135g for a 150-pound person.