This Is Exactly How Much Protein You Should Eat As You Age, From An MD

It's an age-old question in the world of health and nutrition: How much protein should I be eating? Not only is the answer entirely personal (we don't recommend one diet—just the one that works for you!), but it apparently fluctuates depending on your age. 

Here's what functional medicine doctor Frank Lipman, M.D., author of The New Rules of Aging Well, has to say about the matter: As you grow older, your body changes from "production mode" to "preservation mode" when it comes to protein. What does this mean? Well, as Lipman explains on this episode of the mindbodygreen podcast, protein affects the body differently as you age (and, it turns out, you might not need as much as you thought).

Below, Lipman explains protein by the decades, as well as which protein-rich foods are best for different ages. 

"When you're in your 20s and 30s, you want to be strong," Lipman says. "You want a lot of animal protein, which is good for growing and reproduction." Of course, it's still possible to overdo it (you don't want to be eating loads and loads of protein, here), but generally it's A-OK to cast a wider net. 

Here's where the shift starts to arise: "Once you get to 45, you don't need to grow anymore," Lipman says, and too much animal protein will become "preserved" in the body. "We know from research that animal protein has a type of branch-chain amino acid, called thymine, that actually stimulates mTOR (mechanistic target of rapamycin)1." This gene prevents autophagy, which we know is an important process for longevity. "You dont want to stimulate [mTOR] if you want to age well," Lipman adds, "so you want to inhibit that." 

How do you limit that gene? Lipman says to cut back a bit on animal protein. Now, you don't have to literally quit cold turkey—just swap in some more plant protein sources on your plate (Lipman's favorites below). "It's a good idea as you get older to switch from animal protein to plant. [Plant-based protein] doesn't have that negative effect on aging that animal protein does."

OK, so you should cut back on animal protein once you hit 45. Noted. However, Lipman explains that your 60s (and beyond) are the years to focus on muscle mass. "You don't want to lose muscle mass, so your protein needs to increase."

That's not to say you should revert to prioritizing animal protein on your plate: Lipman still believes plant-based sources reign supreme—you just might want to up the ante a bit. "I would increase [your levels] by using vegetable protein, nuts, and beans," Lipman explains. Make sure you have an adequate serving of protein during each meal to keep your muscles strong. 

Lipman suggests the usual suspects: "Nuts and seeds are all good," he mentions. He also loves tempeh (gotta love those fermented soybeans!), as well as a healthy amount of beans. Again, that's not to say you can't eat animal protein at all (we repeat: If it works for you, it works!), but you might want to focus on incorporating more plants into the rotation—their phytochemicals have a ton of other benefits, anyway. 

Although, he does mention one caveat when it comes to animal protein: "Collagen is the one animal protein that does not have those thymine amino acids," he says. "So if you're worried about animal protein, collagen is a great source of protein that doesn't have the negative effect on longevity genes." Keep sipping on your bone broth or proceed with a smart collagen supplement.

While everyone has different protein needs—the exact value does vary—Lipman says that you might need less of that amount as the years go on. And if you're partial to animal protein, you might want to introduce more plant-based sources once you hit 45; consider it the simplest longevity diet there is.

Enjoy this episode! And don't forget to subscribe to our podcast on iTunes, Google Podcasts, or Spotify!