Protein — one of the three macronutrients along with carbs and fat — is essential for human health.
Many types of protein exist in the body. They’re involved in critical bodily processes, including oxygen transport, immune function, the transmission of nerve impulses, and growth (
High protein diets have been linked to a number of health benefits, including improvements in body composition and reduced blood sugar levels.
However, you may wonder whether you can get too much of a good thing.
This article reviews the science behind protein in the diet and whether you should be concerned about eating too much of it.
The amount of protein your body needs depends on many factors, including your weight, age, body composition goals, physical activity level, and overall health.
The Recommended Dietary Allowance (RDA) for protein is 0.36 grams of protein per pound (0.8 grams per kg) of body weight (
However, it’s important to note that this is the minimum intake most people need to prevent muscle loss, meet amino acid requirements, and maintain nitrogen balance. Eating higher amounts of this nutrient may offer some benefits (
Some experts argue that physically active individuals need much higher amounts of protein than the RDA. Many professional organizations recommend 0.54–0.9 grams of protein per pound (1.2–2 grams per kg) per day (
For athletes, needs may be even higher (
Additionally, pregnant and breastfeeding people, older adults, and those with certain medical conditions have higher protein needs than the general population (
For example, the protein RDA for pregnant people is 0.5 grams per pound (1.1 grams per kg) (
However, research shows that daily protein requirements during pregnancy are much higher than this, at around 0.75 grams per pound (1.66 grams per kg) during early pregnancy and 0.8 grams per pound (1.77 grams per kg) in late pregnancy (
Your protein needs depend on many factors, including your activity level, age, and health status. Experts agree that the current protein RDA is likely too low for most active people.
High protein diets have been associated with a number of health benefits.
For example, higher protein diets increase feelings of fullness, reduce hunger, and boost resting energy expenditure, all of which may encourage weight loss.
Studies show that high protein diets promote weight loss and improve body composition in many populations (
One high quality study had 54 women with overweight or obesity exercise and consume either a high protein diet or a low calorie, high carb diet for 14 weeks (
The women who followed the higher protein diet lost significantly more weight and body fat than the women following the low calorie, high carb diet (
High protein diets can also help improve body composition by increasing muscle mass. Studies have demonstrated this in different populations, including trained athletes and older adults (
In addition to improving body composition and possibly enhancing fat loss, high protein diets may increase blood sugar control, reduce blood fat levels, and increase bone density in older adults (
Research has found high protein diets may provide health benefits, including fat loss and improved body composition.
There have been some concerns over the safety of high protein diets, including their effects on kidney, heart, and bone health.
However, most of these concerns are not supported by scientific research.
A common misconception about high protein diets is that they’re harmful to kidney health (
Research has shown that even though high protein diets increase the workload of the kidneys, they don’t negatively affect people with healthy kidney function (
In fact, one study looked at protein intake and kidney function in 48 trained men and women (
Consuming a diet containing 1.5 grams of protein per pound (3.4 grams per kg) for 8 weeks in combination with resistance training did not lead participants to experience any adverse health effects (
It did not change any blood parameters, including kidney function markers like glomerular filtration rate (GFR), blood urea nitrogen (BUN), and creatinine (
Though high protein diets may be safe for people with normal kidney function, people with decreased kidney function should avoid them. High dietary protein may accelerate the decline of kidney function in this population (
The kidneys filter and remove waste products of protein metabolism from the body. In those with decreased kidney function, a high protein diet may lead to kidney damage and the accumulation of toxic substances.
Research has shown that people with kidney disease benefit from protein-restricted diets, as they slow the rate at which kidney function declines (
Some people fear that a high protein diet may increase the risk of heart disease. However, research shows that higher protein diets don’t typically harm heart health.
For example, a study that included 12,066 adults found no association between animal or plant protein intake and increased heart disease risk (
Another 2020 study in 38 adults with excess weight found that a high protein diet did not harm heart health or blood vessel function after a 34-month intervention, compared with a moderate protein diet (
Some research also suggests that higher protein diets may help reduce blood pressure levels, decrease belly fat, and increase HDL (good) cholesterol, which may help reduce the risk of heart disease (
Additionally, a 2020 review found no association between higher total protein intake and the risk of death from heart disease (
However, the study found that higher plant protein intake may have a protective effect against death from heart disease, while higher animal protein intake may be associated with an increased risk (
It’s important to note that some studies suggest that higher protein, lower carb diets may increase heart disease risk factors in specific populations, including Korean men (
Researchers have also argued that excessive protein intake may accelerate atherosclerosis, or plaque buildup in the arteries (
Scientists need to conduct more well-designed studies to investigate the effects of different dietary protein sources and macronutrient ratios on heart health (
Studies have shown that total protein intake is not significantly linked to the risk of breast, esophageal, colorectal, ovarian, or prostate cancer (
A 2020 review found no association between higher total protein intake and risk of death from cancer (
In fact, a 2016 study found that a higher protein intake was associated with better survival rates in women with breast cancer (
However, research shows that specific sources of protein may increase cancer risk. For example, processed meat products are associated with an increased risk of colorectal, breast, and gastric cancer (
Older studies have raised concerns that high protein diets may lead to low bone mineral density. However, more recent studies have shown that higher protein diets may be beneficial for bone health.
A 2019 review of 13 studies found that higher protein intake above the current RDA was significantly associated with a reduced risk of hip fracture and increased bone mineral density (
Furthermore, a 2017 review of 36 studies found high protein intake had no adverse effects on bone health. It also found that higher protein intake may have beneficial effects on the bone mineral density of the lumbar spine, compared with lower protein intake (
Protein is essential for bone health, along with other nutrients, including calcium and vitamin D. In fact, over one-third of bone mass is made of protein (
This is why organizations like the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) recommend higher protein intakes of 0.45–0.54 grams per pound (1–1.2 grams per kg) per day (
High protein intake is not associated with certain major health conditions in most populations and healthy people. However, particular protein sources, such as processed meat, are associated with health concerns.
Protein is essential to your health, and high protein diets have been linked to certain health benefits. However, this does not mean that following a diet very high in protein is the right choice for you.
Keep in mind that the overall quality and nutrient density of your diet is what matters most when it comes to health promotion and disease prevention. The exact macronutrient composition of your diet is less important.
As mentioned above, your protein needs depend on many factors, including your body weight, age, body composition goals, overall health, and activity level.
Most physically active people would benefit from following a diet that delivers 0.54–0.9 grams per pound (1.2–2 grams per kg) of protein per day.
However, others may need more. These people include athletes, those with physically demanding jobs, pregnant and breastfeeding people, and those with certain health issues (
If you’re interested in learning more about high protein diets or unsure how much protein you should be eating per day, talk with your healthcare provider about it. They can help develop a dietary pattern that works best for your needs.
It’s important to choose a dietary pattern that suits your health and wellness goals. Most active people would benefit from a diet that delivers 0.54–0.9 grams of protein per pound (1.2–2 grams per kg) per day.
High protein diets have been linked to a number of health benefits. They’re popular for promoting weight loss, building muscle mass, and more.
Some people may be concerned that high protein diets could harm their health. However, research shows high protein diets are relatively safe and not linked to serious side effects in most healthy people.
If you’re thinking about increasing your protein intake or following a high protein diet, consider working with a qualified healthcare provider like a registered dietitian.
They can help ensure that your diet is nutritionally complete and suits your needs.