Fasting and exercise can increase the longevity hormone FGF21, but what can we eat—or avoid eating—to get the same results?
More than a century ago, fasting was not only recommended as a way to combat “brain disorders,” but also to “prolong healthy longevity.” If that turns out to be true, FGF21 may be the missing link. FGF21 appears to be a “systematic enhancer of longevity.” It can be improved by fasting for a long time, but thankfully, there are other, stronger measures, such as more carbs or less protein.
Give people lots of starchy foods, and their FGF21 levels go up. Healthier sources might be whole grains and beans, as butyrate seems to increase FGF21, too, and we get that in fiber. That’s one of the things our good bugs do with fiber-rich foods.
Circulating FGF21 levels also increased significantly after eating a low-protein diet—more than a 150% increase within four weeks. By the way, “low protein” simply means reducing the amount of protein that most Americans eat to the recommended amount.
The recommended daily allowance of protein for most men is 56 grams of protein per day, although most American men get more than 100 grams. When researchers studied men who had been getting the usual excess of 112 grams a day and reduced it to 64, which is still more than the recommended 56 grams, so the “restricted” protein group still got enough protein—they found that FGF21 levels in the blood doubled. That may help explain why they lost more body fat, despite getting more calories. How can you eat 300 more calories a day and lose another two pounds of body fat? By lowering the protein levels down to a normal level. Who has not thought about a diet that allows you to eat more calories that are easily burned by accumulating fat burning? So, maybe we should “play protein to play metabolism,” thanks to FGF21.
Even a small program of protein restriction to recommended levels can have important clinical benefits. Now, this was a month and a half later. The same study found that a small protein restriction, reducing men to 73 grams per day, caused a sixfold increase in FGF21 within one week, accompanied by a significant increase in insulin sensitivity, as you can see below and at 2:46 in my video. How To Boost FGF21 With A Longevity Diet.Researchers have concluded that protein digestion improves our metabolic health.
Evidence suggesting that a low-protein diet is positively associated with better health, survival, and insulin sensitivity has continued to grow, but we weren’t sure exactly how. Perhaps FGF21 provides an explanation. Interestingly, these studies fed people 9 percent of their calories from protein, which is about what the Okinawans were getting when they were one of the healthiest, longest-living people in the world.
I’ve talked before about methionine restriction to fight cancer and as a life extension strategy. Methionine is an amino acid found mainly in animal proteins, so a person can reach the limit of methionine by avoiding animal foods. That may be an effect of FGF21. Inhibition of methionine increases levels, so much so that it has been called “the most important mediator of metabolic reorganization in methionine inhibition.” Some proteins may be more important to limit than others. The highest levels of methionine are in meat. Vegetables (beans, split peas, peas, and lentils) have three times less methionine than meat, as you can see below and at 3:55 in mine. video.
FGF21 has been suggested as a potential mediator of protection against cancer, autoimmune diseases, diabetes, and obesity, provided by a strictly plant-based diet. Perhaps that’s one of the reasons why a whole-food, plant-based diet has been shown to have such amazing results. Take the example of Dr. Esselstyn, who shows that heart disease—the leading killer of men and women—can be stopped or reversed, and the risk of heart attack nearly eliminated, with the help of a whole-food, low-fat vegan diet. This benefit cannot be explained solely by cholesterol reduction, as we now have powerful cholesterol-lowering drugs that can force cholesterol levels as low as those who eat a healthy diet but appear to have little effect. Therefore, the marked benefits Esselstyn reported seem to reflect various protective mechanisms related to whole foods, plant-based diets, and FGF21 may be one of those mechanisms. So, it’s not just fat and cholesterol—the amount and quality of protein may also play a role. But there has never been a study to see if vegans have higher levels of FGF21…until now.
In addition to studying obese New Zealand mice, the researchers investigated circulating FGF21 levels in those who ate a plant-based diet, then tested it by removing meat from other people’s diets to see if FGF21 levels would increase. They found that FGF21 levels were significantly higher in vegans compared to omnivores, and levels increased when omnivores were switched to a vegetarian diet after just four days. And not just by a small amount—FGF21 levels increased by 232% after just four days of no meat.
The main point is that “various fasting methods are likely to have limited effectiveness, especially in old age and in cases without obesity, unless combined with a balanced diet such as a calorie-restricted diet and a plant-based diet based on the Mediterranean or Okinawa low protein,” meaning the recommended amount of protein.
Doctor’s Note
I introduced FGF21 in the first video. If you missed it, check it out Life Extension by FGF21.
The methionine videos I mentioned Methionine Restriction as a Life Extension Strategy again Starving Cancer with Methionine Inhibition.
