Want to Live Longer? Don’t Try Caloric Restriction

The latest research on caloric restrictions shows that near-starvation diets may not be the Fountain of Youth

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Decades ago, in the 1930s, researchers working with lab rats made an interesting discovery. Animals that had been deprived of food seemed to live longer than rodents that were fed to satisfaction, raising the intriguing idea that maybe near-starvation was a good, rather than bad thing, for health.

Follow up studies, particularly in yeast, confirmed the trend and some forward-thinking scientists even began restricting their caloric intake in the hopes of seeing some extra years. But the latest research conducted on close human cousins, rhesus monkeys, shows that the connection may not be as solid as once hoped.

Published in the journal Nature, the results suggest that dramatically cutting back on daily calories — by 30% — does not help monkeys to live longer than those who ate normally. The restriction did help older monkeys to lower their levels of triglycerides, a risk factor for heart disease, but otherwise conferred no significant health or longevity benefit.

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Caloric restriction may have its evolutionary roots as a survival mechanism, allowing species to survive on scraps when food is scarce in order to continue to reproduce. But that restriction only has lasting positive effects if the overall diet is a balanced one, which may not always be the case in conditions of famine. (That also explains why anorexia is so unhealthy:  people who starve themselves become malnourished). It’s possible the strategy developed as a way to protect species from consuming toxic plants or foods, when it wasn’t always obvious which sources were verboten.

The study, begun in 1987 and one of the longest running trials to investigate the effects of caloric restriction, contradicts the only prior research conducted with rhesus monkeys, which found the opposite effect, highlighting the complex relationship between caloric processing and metabolic functions that contribute to aging and health.

For example, the study’s lead author, Rafael de Cabo of the National Institute on Aging, notes that the effects of caloric restriction on the immune system may not be all good: some studies show slower wound healing and increased risk for infectious disease. In young animals, restricting calories also reduces fertility.

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It’s not entirely clear why the two monkey studies had such varying results. Ricki Colman, a co-author of the first monkey study and an associate scientist at the Wisconsin National Primate Research Center, believes that the differences may reflect variance in the diets given to the animals in the two studies. “They may be modeling different things,” she says, explaining that in her study, the control animals were allowed to eat freely while in the new research, both controls and those on the restricted diet were limited to specific maximum amounts. Her control animals, she says, may reflect more of a typical American diet, while the controls in the new research are more like people who already eat healthy amounts. Colman’s Wisconsin study diet also contained far more sugar— 29% of calories, compared to 4% in the NIA trial. In fact, 40% of control animals in the Wisconsin study developed diabetes, but none of the restricted monkeys did, despite their sugary meals.

“If I told you that eating less would prevent diabetes, I don’t think you’d be surprised,” says Dr. Steven Austad of the University of Texas Health Science Center in San Antonio, who wrote a commentary on the new study for Nature.  He’s spoken to groups of people who have already put themselves on caloric restriction, hoping for longer life.  Rodents on such diets live to the human equivalent of 120-130. But this research suggests “you’re not going to live to 130,” he concludes.

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Indeed, the NIA study implies that the benefits of simply eating a balanced, healthy diet may provide as much life extension as dietary restrictions  can produce. The meals received by both groups of animals in the study were carefully balanced for nutrient content and even shifted with the seasons  as the monkeys’ natural diet in the wild would.

Even with the findings, however, some experts are still holing out hope that restricting calories may prove beneficial for certain health outcomes, specifically in combating cancer and heart disease. The question, of course, is how much restriction can you get away with in order to still get these benefits — and whether a drug could replicate caloric restriction without the self-discipline needed to enforce it. One such possibility, based on a compound found in red wine called resveratrol, is already being tested but its safety and effectiveness in humans has not yet been demonstrated. Austad himself is studying another drug that has shown life extension benefits in rodents called rapamycin, which is already approved to suppress immune rejection in patients receiving organ transplants.

To understand why the NIA and Wisconsin groups got such different results, they plan to collaborate to fully analyze the data generated by the two trials. “We consider our two studies to be complementary, not competitive,” says Colman,  “We have plans to work together to directly compare information from our two studies.” The result, they hope, may be some version of the Fountain of Youth.

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Maia Szalavitz is a health writer at TIME.com. Find her on Twitter at @maiasz. You can also continue the discussion on TIME Healthland’s Facebook page and on Twitter at @TIMEHealthland.


This article is wrong. It cites a scientific study published in the esteemed Scientific journal, Nature, as evidence. Perhaps it was an older study, but I did a quick google search and found this recent article:


The scientific study published in Nature concluded that Caloric Restriction (without malnutrition) DOES WORK, and the conclusions were the opposite of what Time published here. 


While human CR studies are limited, a number of them have produced positive results. For example,  Fontana reported on humans following CR for 6 years and found that many health benefits resulted, including fewer cell replications and lower atherosclerosis. A Spanish study of some years ago also found the CR reduced mortality compared to control group following a normal diet. The Okinawan centenarians were exposed to a much reduced caloric intake during childhood and a moderately lower calorie intake as adults. They have the highest percentage of centenarians in the world. The Chinese in Bama, China have very high percentage of centenarians and consume less 1500 Calories a day. A recent Hawaiian study found that among elderly Japanese Hawaiians, those who ate fewer calories had the best survival rates as long as they didn't go below 970 Calories a day. When the Cubans experienced an economic crisis, their caloric intake dropped below 1900 Calories. As a result, all-cause mortality, cardiovascular disease and diabetes dropped sharply.  During the lean years of WW II, Europeans saw a sharp drop in heart disease. A final point, Song reported that people conceived or born during the Great Leap Forward Famine actually had longer life expectancies compared to those conceived after the end of the famine.

The preceding human findings are supported by CR research with mice, rats, dogs, and cows.

While not as convincing as a human study tracking CR people over their entire lives, I think the findings are quite powerful and worth considering until we have more data.



@ThomasSamaras I just met Dr. Fontana 1 hr ago listening to his talk. The data shown here can be explained by the diet given in group that was used to compare with CR group. @@Kitty Antonik Wakfer You made a very precise clarification. CR vs. SAD equivalent diet did show a significant improvement. However, the NIA group result is interesting in that, we can see a benefit from a consistent healthier diet, which can approach the results seen with CR. People on SAD cannot expect to have the best possible health outcome in long term (it is not the fault of the "conflicting scientific data" when people on SAD have increased mortality and chronic disease conditions compared to their CR-diet neighbors). Yes, this article's title is very misleading, but TIME is not a scientific journal and it does need to generate "clicks" to increase name value for advertisement. The downside is those people who just read the title and make lifestyle decision based on it because the article with such (misleading) title has been published in "TIME." TIME and other media outlet should consider themselves as educational devices rather than generators of eye-catching articles with intermittent ads attached. It is fortuntate that discerning readers like you can post on the article to make clarification. 

Kitty Antonik Wakfer
Kitty Antonik Wakfer

This NIA diet for controls was NOT comparable to Standard American Diet (SAD) and media's resulting negative conclusions about CR - like the title of his one: "Want to Live Longer? Don’t Try Caloric Restriction" - shows a desire to grab headlines without use of facts. Yes, the article content is more reasonable and yes, the conclusion likely will be that primates eating a well nourishing mildly calorie restricted diet will live as long (and as healthily) as those on a diet more heavily restricted calorie-wise.

I and husband Paul wakfer (67 and 74, respectively) have been on mild calorie restriction for 10 years and added intermittent fasting (1 out of 3 days) 3 years ago. Neither of us has any chronic health problems or debilitating disorders, the "plague" of most people our ages.

We will be studying the full Nature published paper by the NIA group, the work of several of whom we are well familiar with for many years. We will be looking for crypto-CR, a known effect in some studies, though not intentional but a result of poor methodology.

Crew Consumers Welfare
Crew Consumers Welfare

The ideal formula is a balance diet and consumed only what the body needs, extra calories must be burnt through physical exercises. Good luck and life will stay longer!


These two studies are several hundred years behind the times. Extensive empirical work was done on CR several centuries ago by Chinese Taoist monks. Researchers would gain far more valuable information seeking out the old mountain temples where their records survive and having the documents translated (assuming they got permission, but if you don't ask....)


From everything I've read restricted calorie diet advocates emphasize nutrition richness -- the best nutrition for the least calories.  Of course starvation is going to cause problems, but you're not supposed to starve yourself on a calorie restricted diet.  Besides, how do they know no one will live to 130 years with this?  Someone lived to 120 recently and only stopped smoking at 116.

Boy, the number of studies that go on to disprove what previous studies proved must be legion by this time.

Darrel K.Ratliff
Darrel K.Ratliff

You restrict calories to have a more healthy live not a longer one  if you avoid too much weight your less likely to get some of the disability diseases (adult onset Diabetes higher blood pressure and lower hdl in the blood to maintain better heart health but with proper health care you can survive as long as the folks on restrictive diets but if you live with chemical cures to those problems often you will have long a life  or( quantity of  time) just not quite as good a quality of it.


Why are we so focused on quantity over quality? 


All of this is just big money for people who claim to have an answer to the American need for excess and lack of desire to move. No one should ever count calories, take a drug, or fret in any way over this. The answer is EXTREMELY simple and won't cost you a dime. There is no need for a book, no need for some MD to tell you what to do.

Eat fruits and vegetables in plenty.  Avoid dairy scrupulously. Exercise daily. Listen to your body's cravings. If you are hungry - eat, and eat well. Your body is infinitely smarter than any MD, research study, or author who writes another reshuffled diet book. You know what's healthy. If it comes in a box with an ingredients list a mile long - it's bad for you - no matter what the box claims it is. 

Again, eat fruits, vegetables, legumes, and if you eat meat, make it lean and sparingly. Exercise daily. Nothing else is needed.

Kathleen Summers MD
Kathleen Summers MD

The biggest lesson here is that an excess of energy intake brings disease, disability, and early death. Restricting intake protects against cancer - and also diabetes, arthritis, and heart disease to some degree, although the numbers in the latest study didn't reach significance for the latter (potentially due to limited sample size). Teasing out just what the optimal amount of intake is takes time and research. And it's complicated - there's nutritional, environmenal, mental/emotional health, and genetics  among other factors playing a role.

The monkeys in both groups of the Wisconsin study ate more and weighed more than the NIH monkeys. The researchers used different sources for their proteins, fats, and carbs as well as a different approach to vitamin and mineral supplementation. 

We have one primate study showing extended life span with calorie restriction and one not showing the same but yet other positive results. Let's not jump to absolute conclusions about what the latter study means.

Kathleen Summers MD PhD


Ian Welch
Ian Welch

Counting calories will get you nowhere. The key is to find a sustainable diet that provides complete nutrition.

Our Refrigerator was recently convicted of attempted murder. It was only after “he” tried to kill me that I realized the danger we were in. In fact, it was while in the ICU following my quadruple bypass surgery , that I figured it out.

Use your Refrigerator as an extension of your overall plan towards health. Use it to represent your goals amp; serve as a constant reminder of your success. When your foundation is solid the rest will follow.

What you stock your refrigerator with is a choice. A choice made long before the food made it home. It is a choice based on thousands of small decisions that confront you daily. Each decision needs to be approached with an overriding master plan. When you select items at the store ask yourself a question: does this belong in my refrigerator. Extend that same question to ordering at restaurants; is this something I would eat at home?

My wife recently received her certification in Plant-Based Nutrition, from T. Colin Campbell amp; Cornell University. One of the first steps she accomplishes when meeting a new client is a WholeFoods walk-through. She has completely mapped out a refrigerator cleansing, essentially replacing the bad with the good...


John La Puma MD
John La Puma MD

The fountain of youth starts in the kitchen.

For longevity, as well as for a healthy weight, doing things that are easy helps humans to establish new patterns. And then, doing them again.  

Caloric restriction is hard for most Americans.

It is not the path to the fountain of youth.

Easy steps, like "Take a sip of water before you eat a meal" help...because then you are on your way to a glass, and to the 3 liters daily you should have. 

But it starts with a sip.



Author, The RealAge Diet, and 

ChefMD's Big Book of Culinary Medicine