Can Protein Restriction Help You Live Longer?

By Guhayavarman | September 16, 2024

“Longevity” is a hot topic right now. Some animal studies suggest that eating less protein might help you live longer. But is this true for humans? Let me share my thoughts on this based on a question from one of my clients.

Q: We know that building and maintaining muscle as we age requires strength training and more protein. Strength training activates mTOR, a pathway that promotes muscle growth. But for longevity, people say we should block mTOR through fasting, supplements like Rapamycin, or eating less protein, especially protein rich in leucine. Can you explain this?

This idea comes from how biological processes might work in theory and from studies on animals, but there’s a big difference between mice and humans.

The Problem with Animal Studies

Most research on protein restriction and longevity comes from studies on animals like mice. Mice live much shorter lives and have faster metabolisms than humans. One human year equals about nine days for a mouse. Because their metabolism is so quick, they process nutrients, drugs, and other substances differently than we do.

This makes it hard to apply what happens to mice directly to humans. For example, in the past, studies suggested that resveratrol (a compound in red wine) could help slow aging in mice. But for humans to get the same dose, they’d need to drink hundreds of glasses of wine daily! When researchers later studied resveratrol in humans, they found no real benefits from it at the levels found in our diet.

Back to Protein Restriction

Now, let’s talk about protein restriction. You might wonder, “If I eat less protein, how many extra years could I gain?”

The truth is, no one knows for sure. To study this in humans, we’d need thousands of people to eat low-protein diets for many years, controlling for all other factors that impact health. Plus, such a study might be considered unsafe because a long-term low-protein diet could cause serious health problems.

However, one study used math models to estimate that eating the minimum recommended amount of protein (about 12% of your daily calories) could add around 3.3 years to your life. But here’s the catch: while you might add a few years, you could risk losing muscle, especially as you age.

The Importance of Protein as We Age

Protein is essential for maintaining muscle, particularly for older adults. As we age, we naturally lose muscle mass, a condition called sarcopenia. This leads to weakness, frailty, and a higher risk of death. That’s why some experts recommend increasing protein intake to about 1.2 grams per kilogram of body weight as we get older.

In fact, many studies show that eating more protein—especially plant-based protein—can improve your chances of healthy aging. For example, a recent study tracked nearly 50,000 women for 30 years. The results showed that those who ate more protein had a better quality of life as they aged.

Not All Protein Is the Same

When people talk about “protein restriction,” they often lump all types of protein together. But there’s a big difference between the effects of processed meats and healthier sources of protein, like chicken, fish, and plants.

Focus on Proven Methods for Longevity

The bottom line is that we need to look at the bigger picture. Longevity isn’t just about one thing like restricting protein. Your overall lifestyle, including regular exercise and a balanced diet, plays a major role in how long and how well you live.

For example, people who sit for more than nine hours a day have nearly double the risk of death compared to those who sit for less than six hours. On the flip side, just 60 minutes of daily activity can cut your risk of death in half.

Several studies show that regular exercise could add 2-4 years to your life—likely more than protein restriction could.

Conclusion

Reducing protein might extend your life by a few years (and that’s a big “might”), but there are plenty of proven ways to live longer and healthier. Staying active, eating a balanced diet, and maintaining a good quality of life are key.

So rather than chasing unproven hacks, focus on strategies that are backed by science. After all, what’s the point of living longer if you can’t enjoy those extra years?