- New research suggests that diets lower in protein may support healthy aging.
- While more data is needed, experts believe low-protein diets may reduce inflammation, among other things.
- Dietitians don’t suggest cutting back on protein just yet.
Protein has been a big focus in nutrition over the past few years. But new research suggests that people may be going overboard on the macronutrient—and scaling back could extend your life.
The scientific review, which was published in the journal Cell Press, analyzed data from more than 350 studies on humans, mice, insects, yeast, and other organisms, and found several biological mechanisms that suggest cutting back on protein could improve a person’s health and lifespan. Among other things, a lower protein intake was linked to better metabolic function, nutrient signaling, and cellular health.
However, protein is a macronutrient—one of the main nutrients your body needs to stay healthy—so you still definitely need some of it. Here’s what experts want you to keep in mind.
Meet the experts: Mir Ali, M.D., medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, California; Keri Gans, R.D., a dietitian and the author of The Small Change Diet; Lisa Moskovitz, R.D., founder of NY Nutrition Group and the author of The Core 3 Healthy Eating Plan
Why might scaling back on protein support healthy aging?
It’s too early to say for sure. However, the researchers laid out a few different theories in their scientific review.
One piece of the puzzle seems to be fibroblast growth factor 21 (FGF21), a hormone that rises as protein intake drops. FGF21 increases energy use and can improve blood sugar management while reducing inflammation. The review cited mouse studies that found that mice with higher levels of FGF21 lived longer than typical mice.
A trio of amino acids—methionine, isoleucine, and valine—also seem to be a factor here. (Amino acids are the building blocks of protein.) Some research suggests that ingesting too many of these amino acids activates biological pathways that can increase the risk of obesity, inflammation, and other health conditions linked with aging.
Still, “it’s hard to make a conclusion that you should limit protein intake,” says Mir Ali, M.D., medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, California. “Protein is important for overall health, and we still need to see a lot more research to determine the optimal protein intake for each stage of life,” he adds.
Lisa Moskovitz, R.D., founder of NY Nutrition Group and the author of The Core 3 Healthy Eating Plan, agrees. “When research like this comes out that majorly contradicts what consumers are being told, it worries me that people will start to get overwhelmed again and go back into the all-or-nothing pitfall with healthy eating,” she says. “This study is interesting, but that doesn’t mean you should throw away all your protein bars.”
What are current protein recommendations?
The latest Dietary Guidelines for Americans suggest having 1.2 to 1.6 grams of protein per kilogram of body weight a day (e.g., a 150-pound adult should have 80 to 110 grams of protein a day). That’s a big increase from the previous recommendation of 0.8 grams of protein per kilogram of body weight.
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However, while there’s been a lot of chatter recently about Americans not getting enough protein, data suggest otherwise. A 2025 study published in the journal Critical Public Health found that American adults who meet the Centers for Disease Control (CDC)’s exercise recommendations, which call for 150 minutes of moderate aerobic activity a week, typically ingest about 82 grams of protein a day. Those who didn’t meet the exercise guidelines had about 79 grams of protein daily, suggesting they’re having too much protein for their needs.
“Many are taking the protein message overboard,” says Keri Gans, R.D., a dietitian and the author of The Small Change Diet.
Some groups need more protein than others
The researchers noted in the study that there are “many unknowns” about ideal protein intake. “While many individuals are likely eating substantially more than the recommended dietary allowance for protein and could benefit from protein or amino acid restriction, some individuals may have a greater demand for protein,” they wrote. Those with increased need include pregnant women, children, people following a calorie-restrictive diet, and people recovering from injuries, per the study. Individuals who exercise also may have high protein needs—or at least be able to take in more protein without seeing a negative impact on their health, the researchers wrote.
Additionally, this was a systematic review that analyzed a series of studies, and each study had a slightly different definition of a “low” protein intake. (For example, one study on rats had those in the high protein group take in 20.4% of their calories from protein, while the low protein group took in 4% of their calories from protein.) This made it difficult for the researchers to pinpoint what “low” level of protein might be beneficial.
How to figure out your own protein needs
Experts say it may be helpful to consider your activity level and age when determining the right amount of protein for your needs. Active people usually need more protein than those who are inactive, Dr. Ali says. But more research is needed to figure out exactly what those amounts are.
It can also be tricky to know if you’re getting in too little or too much protein based on how you feel, Dr. Ali says. “Lack of protein may make you feel tired or more weak, but that’s not always the case,” he says. “And, unless you have a kidney disorder or trouble metabolizing protein, it’s hard to overdo it.”
At a minimum, it’s important to ensure you’re getting an adequate amount of protein. “Protein, along with strength training, is important for preserving muscle mass, strength, and independence as we age,” Gans says. “Cutting back too much could increase the risk of muscle loss, so this is not a reason to drastically reduce protein intake.”
Dr. Ali agrees. “People still need protein,” he says.
If you’re having trouble figuring out the right amount of protein for you, it may be helpful to consult your primary care physician or a registered dietitian. They can order tests to help determine whether you’re meeting your needs, Dr. Ali says.
Overall, Moskovitz recommends aiming for balance in your diet. “Overly obsessing or prioritizing any one nutrient is never the answer,” she says. “Protein is still important and eating too little can have deleterious health effects, but that doesn’t mean you need to eat protein like it’s your full-time job. The message here is everything in moderation.”
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