Protein‑filled foods are everywhere now – from cereal to coffee to water. But a big new review of more than 350 studies says that eating less protein could actually be good for you and might even help you live longer.
Protein Cutting as an Alternative to Cutting Calories
Scientists have known for years that eating fewer calories can make many animals live longer and can lower the risk of diseases like cancer. However, staying on a low‑calorie diet is hard for most people.
Cutting protein may be another way to gain the benefits. Earlier research showed that flies and mice lived longer when they ate less protein, even if they didn’t eat fewer calories overall.
Recent trials with people also look promising. Participants who reduced protein ate the same or more calories, lost weight and body fat, and had better fasting blood‑sugar levels.
When More Protein Is Helpful
It isn’t all one‑sided. Other work shows that higher protein can help people lose weight and can keep older adults’ muscles strong, especially when they exercise.
This helped shape new U.S. dietary guidelines that now recommend 1.2‑1.6 g of protein per kilogram of body weight each day – almost double the old advice.
How Less Protein May Boost Health
The review spotted several common ways that low protein could help the body:
- Better metabolic function.
- Changes in how cells sense nutrients.
- Less damage to cells.
- Improved maintenance of healthy cells.
One key player is a hormone called fibroblast growth factor 21 (FGF21). When protein drops, FGF21 goes up. It can raise the amount of energy the body uses, improve blood‑sugar control, and lower inflammation. In mouse studies, higher FGF21 levels were linked to longer lives.
Specific Amino Acids That May Speed Up Aging
Protein is made of building blocks called amino acids. The review highlighted methionine, isoleucine, and valine. Too much of these may turn on growth pathways that, when over‑active, can raise the risk of obesity, inflammation, and other age‑related problems.
Protein Needs Differ From Person to Person
Some groups need more protein, such as pregnant women and certain older adults. For most sedentary adults, however, protein‑fortified foods may not give the expected health boost.
Athletes can eat a lot of protein without getting sick because regular exercise directs protein toward building strong muscle. The researchers suggest that future protein guidelines should consider both age and activity level, not just a single number for everyone.
This research was funded by the National Institute on Aging, the Wisconsin Partnership Program, and the University of Wisconsin‑Madison.