Amid protein craze, could less of it be better?

It’s hard to walk down a grocery store aisle now without seeing products that are packed with protein. In addition to classic protein sources such as meats and legumes, there’s an arsenal of snack foods, shakes, pastas and more that have protein added. Couple that with all the messaging on social media that you’re not eating enough protein, and it’s no wonder that many people are asking themselves if they should be on a high-protein diet.

High-protein diets have been a favorite of exercise enthusiasts and bodybuilders for years, but with all the hype around protein, more and more Americans are thinking about this macronutrient. While protein provides plenty of perks, like supporting muscle growth and helping you feel full after meals, eating too much can come with serious downsides, according to Jessica Cording, registered dietitian and author of “The Little Book of Game-Changers.”

“I definitely am seeing people taking their protein intake above and beyond what they need,” Cording says.

You might have already heard about the risk of kidney issues, cardiovascular disease and digestive issues if you go overboard with protein, but new research published in the journal Cell Press Blue uncovered another surprising downside of eating a high-protein diet.

Protein intake and lifespan

According to that scientific review, eating less protein could actually help extend your lifespan. For the study, researchers analyzed more than 350 studies on humans, mice, insects, yeast and other organisms and discovered several biological effects that suggest easing up on your protein intake could improve your health and lifespan.

The researchers linked a lower protein intake with better metabolism, cellular health and use of nutrients within the body, among other things.

It’s important to stress that the study didn’t find that eating a high-protein diet will shorten your life. Instead, it found an association between having less protein and living longer.

Further complicating things is that the studies included in the research didn’t have one single definition of what it means to have a low protein intake. (One study in rats classified “low” protein as taking in just 4 percent of their calories from protein, while others had wildly different classifications.) That makes it hard to say what having a “low” protein diet that would potentially increase your lifespan even means.

Still, Cording says there’s food for thought here.

Better for healthy aging?

Again, there are a lot of unexplained variables here. But, in the case of this study, there are a few likely explanations, per the researchers.

One is that cutting back on protein could lead to an increase in fibroblast growth factor 21 (FGF21), a hormone in the body that rises as you take in less protein. FGF21 increases your body’s use of calories and can improve blood sugar management while reducing inflammation in the body. (The researchers flagged a few mouse studies that found rodents with higher levels of FGF21 lived longer.)

Amino acids, which are the building blocks of protein, also seem to play a role. Cutting back on specific amino acids — methionine, isoleucine and valine — might support healthier aging because they activate biological pathways that can increase the risk of obesity and inflammation, both of which are linked with aging.

Much of the concern with a high-protein diet is inflammation, but there are a lot of variables, Cording says.

“It depends on what is driving that inflammation,” she explains. “It also depends on what sources of protein a person is utilizing and what else in their diet. There’s a lot of nuance there.”

Current protein recommendations

The Dietary Guidelines for Americans were updated in January and included changes in protein intake recommendations. The latest guidelines suggest having 1.2 to 1.6 grams of protein per kilogram of body weight a day (meaning, a 150-pound adult should have 80 to 110 grams of protein daily). The previous guidelines recommended having 0.8 grams of protein per kilogram of body weight. No doubt, this has further fueled the protein craze — but it’s important to take these guidelines with a grain of salt.

While messaging on social media suggests that everyone is deficient in protein, research suggests that’s not the case. A data analysis of 7,910 adults that was published in the journal Critical Public Health in 2025 found that American adults who log 150 minutes of moderate-intensity aerobic exercise a week typically have about 82 grams of protein a day. Those who didn’t meet those exercise guidelines took in 79 grams of protein.

“Many people are eating too much protein,” Cording says. “We’re exposed to so much messaging about a high-protein diet that it’s making people overdo it.”

Protein is very important for health and longevity, she says. Cording just recommends aiming for about 30 grams of protein per meal to keep things in check. “Most adults do not need 50 grams of protein in one meal,” she adds. “Your body does great if you stick to 30 grams of protein per meal or so.”

Cording also recommends being aware of other macronutrients when it comes to diet and longevity.

“I frequently see people being so focused on protein that they neglect other important nutrients, like fiber,” she says. “Then, they can become constipated or their cholesterol goes up.”

Too much protein can also raise the risk of weight gain, she points out.

Overall, if you’re struggling to find the right amount of protein for your needs, it can be helpful to check in with your doctor or a dietitian. But Cording stresses that you shouldn’t cut way back on your protein intake for a longer life.

“We still need protein,” she emphasizes.