Proteins are the most versatile molecules for the human body and are key to almost all biological processes. The average recommended dietary allowance for protein is calculated using the ratio of 1 gram of protein for every 1 kilogram of a person’s body weight.
The recommended dietary allowance or RDA for protein depends on factors, such as:
- age
- gender
- pregnancy and breastfeeding
- activity levels
Adults are generally recommended to eat 0.8 g per kilograms (kg) of body weight daily.
According to the Institute for Medicine (IOM), the daily RDA for protein is as follows:
| Life stage and gender | RDA in grams (g) per day |
| Infants and children | |
| 0–6 months | 9.1 |
| 6–12 months | 11.0 |
| 1–3 years | 13.0 |
| 4–8 years | 19.0 |
| Males | |
| 9–13 years | 34.0 |
| 14–18 years | 52.0 |
| 19–70 years and older | 56.0 |
| Females | |
| 9–13 years | 34.0 |
| 14–70 years and older | 46.0 |
| Pregnant or breastfeeding women | |
| All ages | 71.0 |
Being physically active can increase the RDA of protein that people should eat. A 2016 study recommends eating:
- 1.0 g of protein per kg of body weight with minimal activity levels
- 1.3 g of protein per kg of body weight with moderate activity levels
- 1.6 g of protein per kg of body weight with intense activity levels
Anyone who is pregnant or breastfeeding will need to eat a lot more protein than other people.
Some studies have also found that people may need to increase the protein intake as they age.
A 2016 study concluded that older adults should eat more protein than is currently recommended to promote healthy aging.
The researchers recommended that adults should ideally consume protein in the range of 1.2–1.6 g per kg of body weight daily, to prevent age-related muscle loss or sarcopenia.
The study also concluded that these amounts would also improve appetite control, satiety, and weight management.
Share on PinterestConsuming too much protein on a regular basis can cause intestinal discomfort and indigestion.
People can typically consume 2 g of protein per kg of their body weight daily, long-term, without any significant side effects.
Some people, such as elite athletes, may be able to eat as much as 3.5 g per kg of body weight daily without any side effects.
Most research indicates that eating more than 2 g per kg of body weight daily of protein for a long time can cause health problems.
Symptoms associated with too much protein include:
There are serious risks associated with chronic protein overconsumption, including:
- cardiovascular disease
- blood vessel disorders
- liver and kidney injuries
- seizures
- death
Doctors have also linked certain conditions to chronic protein overconsumption:
- type 2 diabetes
- cancer
- osteoporosis and osteopenia
The IOM recommend people get between 10 and 35 percent of their daily energy intake from protein.
Most people can safely eat between 2 and 3.5 g per kg of body weight daily, especially those who need more protein than others, such as:
- athletes
- pregnant and breastfeeding women
- people who do physically demanding jobs
Researchers are still unsure whether very high protein diets are safe, especially when someone is also cutting back on their carbohydrate intake.
Share on PinterestHigh-protein diets may reduce hunger cravings and help with weight loss.
It seems higher protein diets may assist with weight loss.
It is likely that high-protein diets promote weight loss because high protein foods tend to promote a feeling of fullness, helping reduce hunger cravings and overeating.
One small study in adolescent overweight or obese girls found evidence that eating breakfast, especially one high in protein, may help control neural signals that regulate food cravings and reward-driven food behaviors.
More research is needed to understand the full relationship between high protein diets and weight loss.
A large variety of plant and animal-based foods are high in protein, including:
- dairy products
- nuts
- legumes
- seeds
- unrefined wholegrain cereal and wheat products
Not all protein-rich foods are ideal for people looking to lose weight or maintain a healthy diet.
Examples of protein-rich, low-calorie foods include:
- 3 ounces (oz) skinless chicken breast (less than 26 g protein and 113 calories)
- 1 scoop of whey protein (less than 24–26 g and 130 calories)
- 6 oz greek yogurt (less than 17 g protein and 100 calories)
- 2 large eggs (less than 12 g protein and 144 calories)
- ½ cup tofu (less than 10 g protein and 95 calories)
- 2 tablespoons (tbsp) peanut butter (less than 8 g protein and 190 calories)
- ½ cup beans (less than 8 g protein and 110 calories)
- 1 oz almonds (less than 6 g protein and 165 calories)
- 1 cup cooked oatmeal (less than 6 g protein and 165 calories)
- ½ cup cooked quinoa (less than 4 g protein and 110 calories)
Share on PinterestSide effects from protein overconsumption may contribute to kidney and liver conditions.
Some people cannot eat as much protein as others because of conditions that interfere with digestion.
Risk factors associated with developing side effects from protein overconsumption include the following:
- kidney and liver conditions
- low carbohydrate intake
- starvation
- gout
- being deficient in nutrients needed for protein metabolites, including glucose, arginine, glutamine, and vitamins B-6, B-12, and folate
High-protein diets are popular, and studies show that high-protein foods may help to:
- increase satiety or the sensation of fullness after meals
- control and reduce appetite and food cravings
- aid in weight loss and fat mass loss
- control neural stimuli related to food and food behaviors
According to national statistics gathered between 2011 and 2014, most American adults of 20 years of age or more only consumed between 15.6 and 16.1 percent of their daily energy intake from protein.
Most people can, therefore, probably increase their protein intake safely, as long as they are not also cutting back on carbohydrates or have liver or kidney conditions.
People should talk with a doctor or nutritionist before starting a very high-protein diet long-term.
You've probably heard the claims by now: Here's a diet that's delicious, easy to stick with, and guaranteed to help you lose weight effortlessly. Or, perhaps it's supposed to build muscle, protect your joints or prevent Alzheimer's. Whatever the diet and whatever the claim, there's a good chance that it is, indeed, too good to be true.
In recent years, high protein diets are among the most popular, whether the protein is consumed as a supplement (protein shakes for body builders!) or simply a larger than usual portion of a balanced diet (such as The Zone, Atkins or Paleo Diets).
Perhaps you're curious about one of these diets or have already tried them— did you ever wonder whether too much protein might be a problem?
How much protein do you need?
Protein is essential for life – it's a building block of every human cell and is involved in the vital biochemical functions of the human body. It's particularly important in growth, development, and tissue repair. Protein is one of the three major "macronutrients" (along with carbohydrates and fat).
So, consuming enough protein is required to stave off malnutrition; it may also be important to preserve muscle mass and strength as we age. And, in recent years, some have advocated a higher protein diet to rev up metabolism to make it easier to lose excess weight, though success in this regard is highly variable.
- The ideal amount of protein you should consume each day is a bit uncertain. Commonly quoted recommendations are 56 grams/day for men, 46 grams/day for women. You could get 46 grams/day of protein in 1 serving of low-fat greek yogurt, a 4 oz. serving of lean chicken breast and a bowl of cereal with skim milk.
- A weight-based recommended daily allowance (RDA) of 0.8 grams per kilogram of body weight. For a 140-pound person, that comes to 51 grams of protein each day. (You can convert your body weight from pounds to kilograms by dividing by 2.2; so, 140 pounds is 64 kg; multiplying this by 0.8 equals 51). Active people— especially those who are trying to build muscle mass— may need more.
- Based on percent of calories— for an active adult, about 10% of calories should come from protein
- To pay more attention to the type of protein in your diet rather than the amount; for example, moderating consumption of red meat and increasing healthier protein sources, such as salmon, yogurt or beans.
But some experts suggest that these recommendations are all wrong and that we should be consuming more protein, up to twice the standard recommendations. Still others claim that the average American diet already contains too much protein. (Read more about the thinking of experts on this subject in this summary of two "Protein Summits" in 2007 and 2013 organized "to discuss the role of protein in human health and to explore the misperception that Americans overconsume protein." Note, these meetings were sponsored in part by animal-based food industry groups.)
Can too much protein be harmful?
The short answer is yes. As with most things in life, there can be too much of a good thing and if you eat too much protein, there may be a price to pay. For example, people that eat very high protein diets have a higher risk of kidney stones. Also a high protein diet that contains lots of red meat and higher amounts of saturated fat might lead to a higher risk of heart disease and colon cancer, while another high protein diet rich in plant-based proteins may not carry similar risks.
So, when it comes to protein, how much is too much?
It's hard to provide a specific answer since so much is still uncertain and the experts themselves don't agree. However, for the average person (who is not an elite athlete or heavily involved in body building) it's probably best to aim for no more than 2 gm/kg; that would be about 125 grams/day for a 140-pound person. New information could change our thinking about the maximum safe amount, but until we know more about the safety, risks and benefits of high protein diets, this seems like a reasonable recommendation.
What's a protein lover to do?
If you want to maintain a high protein diet, the details matter:
- Find out from your doctor if you have any health conditions (such as kidney disease) that might make such a diet risky
- Get your protein from healthy sources such as low-fat dairy products, fish, nuts and beans, lean chicken and turkey; avoid proteins sources that contain highly process carbohydrates and saturated fat
- Spread your protein consumption across all of your meals throughout the day
- Choose a well-balanced diet that includes lots of vegetables, fruits, and fiber; the Mediterranean diet or the DASH diet are good starting points.
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