Stay Hungry, Live Longer: the Science Behind the Calorie Restriction Diet

An SMU biologist thinks the secret to the fountain of youth may be found by putting fruit flies on a diet.

Carson points to studies that show that calorie restriction followers have healthier glucose and insulin levels as they age, less incidence of inflammatory diseases and do better on cognitive function tests.

"There's something to this idea that getting just the right amount of calories for survival is an important way to manage health," she says. "They find that place where they eat just enough, somewhere between 1,300 and 1,500 calories a day. The body is remarkable in how it adjusts and tries to maintain a steady state to keep you alive and functioning."

The few calorie restriction studies using human subjects involved people voluntarily on the diet already, including one project at the Washington University School of Medicine looking at heart health among several groups, including 28 members of the Calorie Restriction Society who had been eating a CR diet for six years. The CR followers' hearts were more elastic and able to relax better between beats compared to subjects who ate a standard Western diet and did endurance exercise training. That study concluded that leanness helped prevent disease, but only calorie reduction slowed down aging.

The most recent short-term study on CR, conducted at the University of Munster in Germany and published online in January by the National Academy of Sciences, lasted three months and determined that reducing calorie intake by 30 percent improved memory ability by 20 percent in elderly individuals (average age 60.5 years).

Evidence keeps mounting showing the many positive effects of eating less. But is a lifetime of meager meals a guarantee of long life?

The skunk at the calorie restrictors' picnic is longevity expert Steven Austad, Ph.D., author of the book Why We Age and professor of biology at University of Texas Health Science Center at San Antonio. He doesn't believe that either CR or resveratrol will have as much of a "youthening" effect on humans as they do on lab animals. As he's told several conventions of the Calorie Restriction Society in the past, what works on flies and mice fails seven out of 10 times on people.

"We know that CR extends life in some animals, in some it doesn't," Austad says. "Some kinds of mice it works, some it doesn't. Some fruit flies it does, some it doesn't. People who study this tend to forget the experiments in which it didn't work."

Austad says he warns extreme calorie restrictors that "the jury is still out" on whether eating so little will add healthy years. "It might suppress the immune system and you could die from the next flu epidemic," he says. Or you could end up at 80 with muscles too weak to support even a thin body. "It would be extremely interesting and exciting if reducing your food intake would extend your life. But people in the aging community tend to jump on the bandwagon and make the leap from fruit flies to humans a little too enthusiastically."

And resveratrol? "Vastly overstated," Austad maintains. "Resveratrol has never been shown to extend life in any mammal except one—lab mice—eating so much fat that it was like you and I ate nothing but Big Macs every day. Other studies on mice eating a normal diet, resveratrol had no impact on how long they lived. It's an intriguing drug, but we don't have any evidence that it really does anything."

Nature and genetics play a much stronger role in longevity than diet, says Austad. In his research, he's interviewed dozens of people who lived to 100 or beyond. "The ranks of 100-year-olds are not populated by marathon runners," he says. "They didn't exercise. Some smoked for 95 years. They've got a genetic quirk."

Though he believes the first person to live to be 150 is already alive, Austad, 52, isn't hedging his own bets on the actuarial tables. He exercises "fairly fanatically" and doesn't smoke, but he also indulges in the occasional cocktail and he doesn't count calories.

"Here's an interesting thing—I've been to several meetings now of scientists who study calorie restriction, and I look around the room and don't see gaunt, skinny people," Austad says. "Some are slender, some are obese, some are muscular. If you look at those people who spend their lives [studying] CR, very few of them seem to do it themselves."

Back in the humid fruit fly chamber at SMU, Dr. Johannes Bauer laughs when asked if he practices calorie restriction. At 5-foot-7-inches, 140 pounds, the German-born scientist (who looks about 19) never exercises, doesn't take resveratrol and has never been on a diet. "Humans evolved as omnivores. They ate everything in their path," he says.

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Ben Franklin advised in Poor Richard's Almanac: "To lengthen thy life, lessen thy meals." Franklin lived into his 80s at a time when the average life expectancy for men was around 35. If he were around today, he might also advise eating more of thy meals raw.

At a recent potluck supper of the Our Heart of Dallas Radical Health Raw/Vegan Meetup, one of 10 raw food social groups in Dallas organized through Meetup.com, the dining table at host Amy Hirsch's apartment is crowded with uncooked edibles prepared by the 25 attendees (out of 237 members total). Shiny green chard leaves are wrapped around raw bits of cauliflower on one plate, and there's a container of pudding made from soaked hemp seeds and coconut milk. Fresh pineapple, blueberries, apples and other fruits brighten the spread. In the middle of the table sits a large bowl of something resembling wet hair. It's hijiki, a calcium-rich brown sea vegetable the "raw foodists," as they like to be called, eat like noodles.

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16 comments
Singleton_78
Singleton_78

I am 33 yrs old, why does it seem like eating less was easier when I was in my 20's? Is thier a biological or metabolic reason for this? This totally perplexes me. I get 1 hour of cardiovasucular excercise 3 to 4 times per week but it is not having the same effect on my figure as it did when I was just 2 years younger. What should I do about this?

Stephan
Stephan

Dr. J - I thought you where taller then me and I didn't know you weighed less then me - Stephan G

At 5-foot-7-inches, 140 pounds, the German-born scientist (who looks about 19) never exercises, doesn't take resveratrol and has never been on a diet. "Humans evolved as omnivores. They ate everything in their path," he says.

Rick
Rick

Obesity and overweight pose a major risk for chronic diseases. That's about 2/3 of the population yet no doubt the same group that banned public smoking (due to health concerns ha ha)

When will fat and obese people be taxed for driving up health care costs for the good people who don't eat eat eat? They drive up health care costs more then smokers did plus they cause accidents... Have you ever seen an overeater try to drive? They can hardly back a car up because they can not turn around to look behind them... overweight people should be given a restricted license as well.

Quit eating so much and try this restricted diet.

Lukka
Lukka

This is really great article about losing weight on healthy way...

Jill
Jill

Just to correct a bit of misinformation in the article:

Eating vegan or raw is NOT a variation on the calorie restriction diet. The vast majority of vegans and raw foodists have chosen their diets for health, environmental and animal abuse reasons and do not purposely eat fewer calories than is currently deemed necessary.

Jill
Jill

Just to correct a bit of misinformation in the article:

Eating vegan or raw is NOT a variation on the calorie restriction diet. The vast majority of vegans and raw foodists have chosen their diets for health, environmental and animal abuse reasons and do not purposely eat fewer calories than is currently deemed necessary.

Stevemle
Stevemle

To Tim's comment:"I would rather die middle-aged and happy than be old and miserable."

I say: "Don't knock it, until you try it. You might surprise your self."

SS
SS

"Vyff now eats once a day, usually a lean chicken breast poached in water, some steamed broccoli or squash and maybe a glass of fresh orange juice. She eats red meat once every two weeks and prefers it cooked rare. Her daily calorie count hovers around 1,200 if she's not exercising"

This is complete BS. If she eats ONCE a day and that once a day is a lean chicken breast poached in water w/ veggies and MAYBE a glass of OJ she isn't coming anywhere NEAR 1,200 calories per day. That is probably a max of 300 calories. The math here doesn't add up in the least.

George
George

So SMU professor wants us to eat 6 walnut halves (3 walnuts) and 3 chocolate chips.

Some of the SMU students already do this, so it shouldn't be too hard. Except that THIS IS AN EATING DISORDER, NOT A HEALTH BENEFIT.

Harris
Harris

Well we certainly shouldn't be publishing information intended to help people make nutritional choices on the basis of fruit fly studies and children's book authors.

Quack medical advice like this is hurting people for a few quick bucks.

Express your distaste for such dangerous nonsense by not buying the Observer.

izz
izz

"Vyff now eats once a day, usually a lean chicken breast poached in water, some steamed broccoli or squash and maybe a glass of fresh orange juice. Her daily calorie count hovers around 1,200"

One meal a day does NOT come to 1,200 calories, even at McDonalds. One serving of veggies, oj & chicken has less than half that amount.

This woman needs to see a nutritionist. Calorie restriction is defined as getting your dietary needs met with vegies, fruits, beans & wholegrains. Living on three chocolate chips is the definition of anorexia.

S. Gupta
S. Gupta

The red wine extract resveratrol is a calorie restriction mimetic, in other words it mimics the effects of calorie restriction without the need to reduce calorie consumption.

Since the Harvard resveratrol study on aging by Dr. Sinclair was published in the journal Nature a flood of dubious companies have sprung up selling resveratrol. Many have no scientists, no labs, no quality control and no experience. Both I and Dr. Mehmet Oz have recommended Biotivia Bioforte and Transmax. They are made by a company with 18 years of experience, and Biotivia supplies many of the university medical schools, health ministries and researchers.

Consumer Lab, an independent testing authority, evaluated the major brands and found many lacking in content and quality. The highest potency products that passed their evaluation were Biotivia, Transmax and Bioforte. A product by Life Extension Co. failed badly with only 26% of the claimed resveratrol. This is clearly a case of buyer beware. Look for a reputable company with the resources necessary to product this compound.

tina
tina

"Vyff now eats once a day, usually a lean chicken breast poached in water, some steamed broccoli or squash and maybe a glass of fresh orange juice. ... Her daily calorie count hovers around 1,200 if she's not exercising; 1,600 to 1,800 if she runs 5 or 10 miles on the treadmill."

This doesn't compute at all. One chicken breast, some broccoli, and a glass of orange juice is nowhere near 1200 calories. (Unless it's a whole jug of orange juice and some mutant chicken breast.) I personally also eat approximately 1000-1200 calories on a daily basis, and I eat lots more than that - Breakfast, lunch, dinner, and at least one or two snacks.

Tim Covington
Tim Covington

I would rather die middle-aged and happy than be old and miserable.

Diana Ivette
Diana Ivette

That´s true. People often tell me they are envious of how much food I eat without gaining weight. But I think it's not about how much you eat but what you eat and the variety in your diet.

For example while most people drink a glass of orange, i eat the whole fruit, which is more satisfying and has less calories. I eat vegetables of all colors before eating the main course, whatever it is, I try to adapt. If i eat a hamburger i don't put dressing on it, and change the fries for salad, and that doesn't make it less appetizing. For dessert I choose a fruit or have some ice cream. I have no problem with it. I enjoy what i eat. In fact I've never liked dressings and fatty food too much.

By the other side, I can see that most of the people who are dieting eat little plates of lettuce with lots of dressing to have a less terrifying experience, and end up with the feeling of being miserable and hungry asking themselves why if they eat so little, they still stay fat.

The point is that my daily count is low and I eat much more than a piece of chicken and steamed broccoli. That's miserable and unnecessary. I love food and love to be healthy too.

 
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