Americans have an obsession with protein. Yet we actually get more than we need: A recent study revealed the average person consumes nearly twice as much protein as the USDA recommends, and despite that, we are on an endless search for more. And what is all the extra protein doing to our bodies? You might think that since protein is the building block of muscles, among other things, more is better, but in fact, the opposite is true: Too much protein can lead to inflammation, weight gain, and health woes.

So just because certain high-protein foods are associated with health benefits, including muscle growth, tissue repair, and immune health doesn't mean you can't overdo it. So before you eat another protein bar or reach for your favorite protein shake for the sake of “good health” learn how this essential macronutrient can, when you overdo it, lead to serious long-term health problems.

How much protein do you need?

Protein requirements vary from person to person and the amount you need will depend on your age, weight, gender, and activity level as well as your health status. “Certain individuals may be able to tolerate higher amounts of protein," explains Sarah Schlichter, RD, and founder of Bucket List Tummy. "Some people have higher protein needs to begin with – such as during pregnancy and lactation, or athletes with intense training schedules.

The general consensus is that most adults should be consuming a minimum daily average of 0.8 grams of protein per kilogram of body weight." That works out to about 50 grams per day for a 140-pound woman and 65 grams for a 180-pound man. Most Americans, especially those who are health-conscious and exercise regularly, are already eating significantly more than that.

Generally, it's safe for healthy adults to consume up to 1.7 to 2.0 grams per kilogram of body weight, or roughly double the recommended amount, especially those with higher needs, says  Schlichter, adding: "If you’re unsure of what amount of protein is right for you, talk to a dietitian who can help you understand how to safely bump up your protein intake without exceeding your upper limit."

According to the National Kidney Foundation, it’s important to eat the right amount of protein to control the accumulation of waste products in your blood, since too much protein can overtax the kidneys and lead to renal failure, according to studies. (Of course, not getting enough protein can cause other problems, so make sure to eat the appropriate amount, but inadequate protein intake is extremely rare in the US and other developed nations.) Protein is in most foods, to a certain extent, and it's easy to get plenty of protein on a plant-based diet.

Is too much protein bad for you?

Regularly eating high amounts of protein is associated with a myriad of adverse health outcomes. For example, Emily Clairmont, MS, RD, from the University of Vermont, says, “Consuming too much protein can result in an imbalanced gut microbiome (due to lack of fiber intake) as well as dehydration, because our bodies needs more water to flush out excess nitrogen (a byproduct of protein metabolism) instead of using it for other important bodily functions.”

Kidney disease

Excessive protein intake may have more severe health consequences, such as kidney issues. Clairmont says, “Too much protein can harm the kidneys, especially in individuals with pre-existing kidney disease or co-existing conditions that affect the kidneys, such as chronic kidney disease, high blood pressure, recurring kidney stones, and diabetes.”

The ratio of plant protein to animal protein is vital for overall health, too. Animal proteins contain high amounts of chemical compounds called purines, which are broken down into amino acids and uric acid — a toxic waste product in your blood.

Too much uric acid in your system and your kidneys need to work harder to cleanse the blood. Diets high in animal protein may also cause an accumulation of toxic protein metabolites. Researchers from the 2020 study recommend increasing your portion of plant protein to animal protein. The ideal ratio seems to be getting half to two-thirds of your protein from plant sources for optimal health.

Like any macronutrient, eating excessive amounts of protein may cause your body to store the protein as fat for future energy reserves instead of using it for muscle development and immune support. This can lead to weight gain if you’re sedentary. Schlichter warns that too much protein on your plate means you’re overcompensating for other nutrients. She says, “Eating excessive protein can lead to nutrient deficiencies and gastrointestinal symptoms like constipation and indigestion.”

Protein and testosterone

In a 2022 study, high-protein low carb diets were associated with a lowering of testosterone in the body. In a meta-study published in the March 2022 issue of Nutrition and Health, nutritionists at the University of Worcester in the U.K. reviewed 27 studies to assess the impact of low-carb and high-protein diets on testosterone levels. They also measured how low-carb and high-protein intact elevates the stress hormone cortisol, since these two hormones are closely linked. Higher cortisol levels correlate to lower testosterone levels.

The research looked at diets of 309 healthy adult males assigned to low-carb or high-carb diets. The low-carb particiants had eaten high protein diets, where at least 35 percent of their total calories came from protein. The low-carb groups ate normal amounts of protein.

The researchers found that men who had followed the high-protein, low-carb diets saw testosterone levels decrease by an average of 17 percent, while cortisol went up.

We’re eating too much of everything


It’s not just protein that we’re consuming in excess. Americans are eating more than ever. According to the Pew Research Center, The average American consumed 2,481 calories a day in 2010, or 23 percent more than in 1970. Today, that number is even higher: Americans eat an average of over 3,680 calories a day — an amount way over the recommended intake of 2,000 for women and 2,500 for men – according to the Food and Agriculture Organization.

Why is this a problem? Eating too many calories raises the risk for obesity, elevated blood pressure, high cholesterol, type 2 diabetes, and even cancer. What’s more of an issue is that these excess calories aren’t coming in the form of healthy whole foods. According to the report, the average American is loading up on ultra-processed sweets and fatty convenience foods high in refined oils and sugars rather than getting most of their calories from whole foods.

The good news is that preventing adverse health outcomes and reducing your risk of chronic disease is entirely within your control. How? Simply by eating less and adding more whole plant foods to your diet. In his book, The Cancer Code, Dr. Jason Fung, MD, explores how restricting calories in a healthy way through fasting methods (i.e., intermittent fasting, fasting-mimicking diets) can help prevent cancer and other chronic diseases, maintain a healthy weight, and even reverse type 2 diabetes.

Bottom Line: Eating too much protein poses long-term health risks.

Protein is an essential macronutrient with many health benefits, but Americans consume far too much, negatively impacting their health. Optimize your health by getting your protein from whole food plant-based sources. Eat protein in moderation and within a healthy caloric range. Consider fasting methods to reduce your disease risk and improve long-term health.

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