Do You Want to Live Past 100 With Chronic Restraint or Intermittent Feasting?
“They’re absolutely the same . . . the claims are basically the same.”
Aubrey de Grey on caloric restriction and intermittent fasting and how they cannot extend lifespan
Aubrey de Grey is the most well-known figure in the longevity or anti-aging immortality movement. He’s a gerontologist who has become the public voice pushing for research to end aging and biological death. Is he correct about caloric restriction and intermittent fasting and their physical effects on your health? Are they the same?
What is Caloric Restriction?
Mary Crowell and Clive McCay at Cornell University discovered in 1934 that laboratory rats lived twice as long if they ate a diet with a reduced number of calories that still contains the required micronutrients. Since then, many studies have duplicated and extended the same results.
It hasn’t been proven to extend the life of human beings, but there are strong indications it improves health.
In general, the smaller the animal and the shorter its lifespan, the greater percentage benefit it receives from CR. Of two studies with primates, one demonstrated CR had no life-lengthening effect, but the other did.
Whether CR extends the life of people is still an open question. However, that does not stop some people from practicing it, such as members of the Calorie Restriction Society International.
Experiments With Human Life Extension Have an Inherent Problem
Before scientists can “prove” whether CR, or any other practice, extends life, they must carry out experiments. There must be a control group and a group that practices CR. Both groups must contain enough people to be statistically significant. Then they must be tracked.
But who’s going to track other people until they die? If the intervention works, then the group of people practicing it will live longer than the scientists who are carrying out the experiment.
And you have to be alive to collect a Nobel Prize.
Even the studies of CR on monkeys took around 25 years to complete, and monkeys live a lot shorter lives than people do.
Therefore, obviously, scientists seeking to extend human lifespan work to improve biomarkers of health and aging, and hope that reducing signs of normal age will result in a longer lifespan. If something apparently improves cardiovascular health, everybody hopes that will prevent or, at least, delay, heart attacks.
The Second Major Problem With Many Studies of Human Beings is Compliance
People can volunteer for scientific studies, but if that doesn’t mean they will go along with the program 100%. That’s especially true of anything that is inconvenient or uncomfortable, such as dietary changes and exercise.
Some studies use people who live in nursing homes and other institutions because they can be better monitored and controlled, but even they are not slaves who can be forced to enjoy eating 30% fewer calories than their preferred meals.
CR Closely Matches the Common Experience With Dieting
Most people who try to lose weight by dieting, unless under the influence of a particular book or fad, simply reduce their caloric intake. They continue to eat regularly, but switch to low calorie foods or simply eat less.
Initial success may keep them going for a month or so, but eventually their frustrations and cravings win out over their self-control, and they go off the diet. Soon, they weigh as much or more than before.
In 1944, Ancel Keys ran experiments keeping people on inadequate diets designed to mimic that of European civilians during World War II. The men who participated, although volunteers motivated to help out, suffered physically and emotionally.
The main difference with CR diets in scientific studies and ordinary dieting is that the scientists strive to make certain their subjects receive adequate nutrition. However, there’s no evidence that substitutes for consuming bulk and calories.
CR Does Lower Some Aging-Related Biomarkers of Risk
On average, people participating in this study:
* Lost 10% of their weight within the first year
* Decreased their blood pressure by 4%
* Decreased total cholesterol by 6%
* Decreased C-reactive protein by 47%
* Greatly decreased insulin resistance
* Reduced T3 thyroid hormone activity by 20%
A few of the subjects had anemia and a decrease in bone density.
The decrease in C-reactive protein is quite significant because that is a marker for silent inflammation, a condition behind chronic diseases and aging.
This also applies to insulin resistance, which is associated with diabetes and other diseases of aging.
Therefore, you must conclude, CR does improve overall health.
Two Big Questions Remain
1. How many of the subjects in that study continue to practice CR?
2. Do people practicing intermittent fasting get the same or better results?
What is Intermittent Fasting?
Definitions and practices vary, but it’s basically the practice of skipping meals for from 12-72 hours.
Most people practice IF through not eating for from 14-18 hours per day or by not eating for a full 24 hours one or two days a week, or some combination of the two.
Some popular variations are called alternate day and 5:2. In these versions, people eat normally every other day or five days a week, but restrict themselves to 500-600 calories the other days of the week. Technically, unless the 500-600 calories come in one meal early in the day and they go without for the rest of the day, this is not fasting, but intermittent calorie restriction.
Technically, Intermittent Fasting is a Variation of CR
As normally practiced and enforced on laboratory animals, CR restricts calories at every meal.
IF does not restrict how much you eat for your meals, but does time-restrict how many meals you eat. Therefore, in practice, you wind up eating fewer calories than all-day-and-half-the-night feeders.
(With IF it is possible to eat so much food that your overall calorie intake does not change. That is especially true when people first begin IF. When it’s finally time to eat, they are emotionally hungry and overeat to make up for the meals skipped. However, for this article I’m assuming the person is motivated to lose weight and obtain the related health benefits. Also, after people become used to missing a few meals, they adapt to it, and therefore, when they do eat, consume just a normal-sized meal.
(In this interview, Dr. Pompa explains how gets good results from IF by eating to satiety when he does eat.)
Intermittent Fasting Comes With a Lot of Benefits
* Lower weight
Consuming fewer calories helps people lose weight
* Lower insulin
It’s food (carbohydrates and protein) that stimulates your pancreas to release insulin. No food, no insulin.
* Higher levels of Human Growth Hormone
* Increased expression of beneficial genes
This includes sirtuins.
* Reduced C-reactive protein
* Greater resistance to destruction by free radicals
* Increases in Brain Derived Neurotropic Factor (BDNF)
And this article sees benefit from IF in reducing stroke risk
Does Anybody Believe Paleolithic People Practiced CR or Dieting?
Many experts base modern dietary advice on what worked for paleolithic people.
And, you might say, cave people did practice caloric restriction. They had an uncertain supply of food. They didn’t have refrigerators or supermarkets. They hunted, and sometimes couldn’t find and kill anything.
Yes, that’s all true. What I mean by “dieting” is CR as often advocated, where people eat small meals throughout the day.
Let’s say you’re a cave man. You and your buddies have just killed a woolly mammoth. You didn’t eat anything that morning. You’ve been too busy hunting the woolly mammoth to eat anything all day. You’re cutting the meat off it to take back to the cave for the women to cook.
That night, did any of those people hold back from gorging on woolly mammoth steaks? No, it is ridiculous to think so. Yes, they often went hungry. All the more reason to stuff yourself silly when food was available.
I’m sure they did the same when they found eggs in bird nests, trees and bushes full of ripe fruit and river beds containing lots of tasty shellfish. When they had food, they ate it. Stuffed themselves like wealthy Romans, though not to the point of vomiting.
And that was only practical. Food spoiled quickly. They not only didn’t have refrigerators, they didn’t have aluminum foil or Tupperware. They couldn’t set food down on a rock, even wrapped in banana leaves, without attracting ants, flies and rodents.
Woolly mammoth corpses were very large, but whatever the hunters couldn’t carry away that day, was gone by the next morning, eaten by hyenas, jackals and vultures.
The human body evolved to survive periods without food, but there’s no sign evolution expected people to remain hungry when food was available.
Only Okinawans manage to do that.
Hara Hachi Bu
In fairness, one culture does seem to practice CR successfully, and it seems to work for them.
That’s Okinawa. “Hara Hachi Bu” means to leave the meal when you feel 80% full, and it’s a Confucian teaching. I’ve never heard of it among Chinese, other Japanese or other Asians influenced by Confucianism, so maybe Okinawans are the only Asian culture to continue it.
They have the world’s highest percentage of centenarians. And, according to Wikipedia, they are the only culture in the world that does voluntarily practice CR.
Hara hachi bu probably does contribute to that, but so do many other factors such as what they eat, their lifestyles and their high levels of physical activity.
This article exhaustively analyzes and compares the scientific studies and determines that IF improves health just as much or more than CR.
It mentions intermittent fasting is easier to comply with, but does not fully take into account the psychological and emotional factors.
It can take several weeks to get used to, but after a while, motivated people can and do skip breakfast most or all days. Or go without food for 24 hours once or twice a week.
Because they know that when they do eat, they will eat until they feel full.
If Anybody in the History of Dieting Was Motivated to Keep the Weight Off Through the Long-Term, It was Dr. Stuart Berger
We know from Ancel Keys’s study on semi-starvation and the typical person’s experience trying to lose weight by dieting, few people can continue that for long. Most abandon it while they’re trying to lose more than 10% of their starting weight.
We also know most people who do successfully take the weight off, eventually gain it back.
At one point as a young man, Berger weighed 420 pounds. He managed to lose half of that, and went on to write bestselling books and to make millions of dollars selling weightloss and dietary advice to the rich and famous. He told people to eat lots of steamed broccoli and to subsist on from 740 to 950 calories per day.
Obviously, Berger himself ate something besides broccoli, and more than 950 calories per day.
Like Aubrey de Grey, Many of the Scientific Studies Treat IF and Alternate Day Reduced Caloric Intake as Equivalent
That’s probably true for many health consequences, but how can it be the same for autophagy and mitophagy? For your body to get serious about repairing and recycling its resources, it needs the “signal” of no calories coming in for 12-16 hours. When you eat, even if it’s just a little bit, you are inhibiting those processes.
And autophagy and mitophagy are more important than just a little biological spring cleaning. They eliminate cells and mitochondria with damaged DNA, which may help reduce the risk of cancer.
To Paraphrase Mae West, I’ve Starved and I’ve Feasted. Feasting is Better.
However, not continuously. I know that intellectually, but my metabolism is not ready to give up feeling full
I’ve fasted and I’ve feasted. It’s a lot easier to alternate between the two than to feel continuously hungry. Old Okinawans may leave the table when they’re 80% full, but not me. But I am capable of completing avoiding the table for several meals a day.
Like most people, I’ve tried to lose weight just by eating less. It didn’t last long.
But I’ve been on the 24-hour two times a week version of IF for over a year and a half. Sometimes I’ve lapsed due to traveling and other personal issues, but I’ve lost around 6 inches around my waist. I don’t have a scale, so I’m not tracking pounds, but they’re significant.
I’d like to say I’m going to live past 120 years old. Ask me that again in 60 years, and see if I answer.
In the meantime, my waist is gradually shrinking and I feel great.
With all due respect to Aubrey de Grey, and I sincerely hope his efforts to extend human life and health spans are more successful than he dreams, I submit that, while the long-term biological effects of CR and intermittent fasting may be similar, the experiences of practicing them are quite different.
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