Americans are getting more protein than they need. They’re not getting enough fiber. And there’s growing evidence that the result could be bad for health.

Vox says we’re “oddly obsessed with protein,” eating twice the dietary recommendation, and “60% of U.S. adults are trying to get even more of it into their diets” — an obsession that could be increasing the risk of cancer and heart disease.

There are certainly reasons to be concerned about getting enough protein. As GoodRX Health explained, “Protein deficiency can be a serious health risk and it’s a common cause of malnutrition in other parts of the world. Protein is a macronutrient, after all, meaning it is required in large amounts in the diet for proper growth, development and overall health.”

But there’s a problem with overconsumption, the article says. “Overloading your diet with protein can mess up your macronutrient balance. Eating high amounts of protein is usually achieved by eating lots of meat and dairy products and these are often high in saturated fat and low in fiber.”

The result can be too much of the so-called bad cholesterol and an increased risk of heart disease and cancer. On the other hand, “plant-based proteins (e.g., beans, grains, soy, nuts and seeds) are lower in saturated fat, high in fiber and rich in micronutrients like vitamin K and potassium (which Americans tend to not get enough of),” per the article.

According to the federal government’s Dietary Guidelines for Americans, 2020-2025, healthy protein foods include “lean meats, poultry and eggs; seafood, beans, peas and lentils; and nuts, seeds and soy products.”

As The New York Times explained in 2016, “People need sufficient protein in the diet because it supplies indispensable amino acids that our bodies cannot synthesize on their own. Together they provide the essential building blocks used to make and maintain muscle, bone, skin and other tissues and an array of vital hormones and enzymes.”

But the Times article notes that Americans likely consume too much, since it’s fairly easy to get the recommended amount of protein — 56 grams for men and 46 grams for women each day — simply by eating without supplementing with protein drinks or powders, which many people do. The Times noted a cup of chopped chicken has about 44 grams of protein, while a cup of tofu or a serving of Greek yogurt has 20 grams. Three eggs provide 18 grams.

Add in a protein bar or shake and it’s easy to overdo unless you’re paying attention.

Overconsumption of protein

Nearly a decade ago, the National Health and Nutrition Examination Survey found men average nearly twice what they need, at about 100 grams of protein each day. The revised Dietary Guidelines for Americans said men and teenage boys in particular should “reduce overall intake of protein foods” and eat more vegetables. While teenage girls and older adults may not get enough protein, most American adults are getting too much.

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Among concerns in the Times article, protein-rich foods don’t preserve muscle mass over time and a high-protein diet can lead to kidney disease for some. Some studies have suggested that too much protein can increase the risk of heart disease, cancer and other problems.

“One study led by Valter Longo, the director of the Longevity Institute at the University of Southern California in Los Angeles, followed a nationally representative sample of 6,381 adults. It found that those who ate a high-protein diet between the ages of 50 and 65 were four times more likely to die of cancer than those who consumed less protein,” per the Times.

Others say there’s not enough evidence to make the claim.

Scientific American notes another problem from excess protein consumption: In 2022, it reported that “protein-packed diets add excess nitrogen to the environment through urine, rivaling pollution from agricultural fertilizers.”

Even if it’s not bad for human health, the article said, “This excess does pose a problem for the country’s waterways. The nation’s wastewater is laden with the leftovers from protein digestion: nitrogen compounds that can feed toxic algal blooms and pollute the air and drinking water. This source of nitrogen pollution even rivals that from fertilizers washed off of fields growing food crops, new research suggests.”

What about fiber?

Eating Well notes that fiber is not a favorite food topic for most people — but it’s vastly important. Fiber is found in fruits, vegetables, whole grains, beans, legumes, nuts and seeds, in two forms — soluble and insoluble. Both are important to health.

The article said those who consume lots of fiber have less risk of heart disease, cancer, Type 2 diabetes and obesity. But only 5% of Americans meet the recommendations for fiber intake.

Among other things, inadequate fiber intake can lead to chronic inflammation, which is linked to the above-mentioned health woes. Immune systems aren’t as strong. Weight is harder to manage. And either constipation or diarrhea are possible, as are hemorrhoids, increased risk of colon cancer, inflammatory bowel disease and other ills.

One way to get both protein and fiber is to choose plant-based proteins more often and cut back some of that from meat and dairy.

Too little protein has its own problems. said these are symptoms of not getting enough:

  • Swelling.
  • Changes to hair and skin, including hair loss and graying or dry, thin or peeling skin.
  • Getting sick more.
  • Muscle loss and weakness.
  • Decreased bone density.
  • Stunted growth.
  • Weight loss or gain.
  • Anemia.

One more food worry

Protein and fiber aren’t the only concerns when it comes to healthy food habits for Americans.

Harvard researchers recently said that Americans are also making themselves sick because of ultra-processed foods. In a recent post, Harvard researchers say those foods make up the “bulk of the American diet” — and largely explain the bulk of the American people, more than 40% of whom are obese, according to the Centers for Disease Control and Prevention, per the blog.

In the Harvard research, participants were randomly assigned to an ultra-processed or unprocessed diet for two weeks. Although the two groups were matched for nutrients, they found the ultra-processed group ate about 500 calories more per day than the other group, gaining both weight and body fat. Those who consumed minimally processed foods “spontaneously lost weight and lost body fat.”