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CRON diet: Calorie Restriction with Optimal Nutrition

This thread can be a general discussion about this intriguing diet which studies have proven to increase lifespan. Mice put on this diet were more active, energetic and lived 30 percent longer. Not sure where the exact link for the study is, but calories were reduced almost to near starvation.

Some people reduce calories to a little under 2000 a day (30 percent less than the average American) and eat foods dense in nutrients (lots and lots of vegetables and fruits). Some people dramatically reduce calorie intake and replace with supplements. In fact, I think I ran into an article a while back (which I conveniently cannot find) of a Chinese man who claims to have not eaten for a couple decades.

Barbara Walters had a great segment "Live to be 150" on ABC discussing this unusual lifestyle, you can find the clip here on this link:


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  1. I think a pint of Haagen Daz is 1600 calories -- that wouldn't work, would it?

    I know, it wouldn't. The concept of this 'lifestyle' is intriguing, but as I saw from a show on it, the practice looks as boring as watching paint dry. A number of people abandoned it out of boredom.

    Are the extra years worth it? I don't think so.

    1. Here's a 2006 article from New York Magazine on this subject:


      But this thread probably belongs on the imaginary "About No Food" board.

      1. That would be a difficult (and not fun) diet for me to follow. But if you want to live to 150 (and don't care too much about food -- believe me, there are people like that) go ahead. A lot of monks essentially do that as some of them only eat once a day.

        1 Reply
        1. re: Miss Needle

          I believe some people who are unwilling to give up some of their favorite foods simply fast every other day or eat once a day. Not sure if that is as effective but they say it's the excess calories that get to you the most

        2. Well, for CHers who "live to eat", that would be hell to live longer and not enjoy food... As the joke goes, you might not live longer but it'll feel like it.


          And, of course, the bummer would be to find at 80, after a lifetime of restriction that it only works on selected rats.

          5 Replies
          1. re: chowser

            I think they did a study on Holocaust victims that went for long periods without adequate nourishment and found that they lived longer years. Not sure how reliable the study is though, plus it's pretty morbid to think that you'd have to go through that much pain just to live an extra decade or so.

            Evolutionary theorists think that calorie restriction increases lifespan because the body goes into "protection mode" in order to prolong the lifespan and allow for more chance in reproductive success.

            1. re: takadi

              Actually, according to the Traditional Oriental medicine perspective, calorie restriction makes perfect sense. But it's probably too off-topic and can get a little involved for me to get into.

              Calorie restriction is one of the reasons why some groups engage in fasts. I do know several people, while not fasting every other day, fast once a week, with longer fasts during the change of seasons for health purposes. I don't think this type of lifestyle is for everyone. Some people are way too deficient to handle it.

              1. re: Miss Needle

                There is another theory of fast and famine for longer life, too. It's like a combination of a "normal" diet and the CRON diet. I don't remember the details anymore but you cut back calories and then have a day when you can eat more.

                1. re: chowser

                  Sounds like the Weight Watchers points diet where you can indulge on the weekends. Of course, the purpose of WW is to lose weight, not to live longer.

              2. re: takadi

                But, the correlation of the victims living longer isn't causation. It could be that the ones that survived were stronger to begin with, or many other reasons. I understand the theories behind it but I, personally, don't think there is enough proof to go on the diet in case I might live longer, miserably and longer. Hmmm, even if there were proof, I wouldn't want to live a life like that.

            2. Just wanted to contribute yet another article on the topic, from Slate, discussing the extension to which CR is actually comparable to anorexia (psychologically speaking):


              1. 2000 calories doesn't seem too restrictive to me, how is that "unusual". I've been living about or under 1200 for a while now (minus a day or so of rare "treat days" while travelling etc...ever so often). My diet is heavy on vegetables, grains,soy, beans etc.....and i'm neither non-gourmet or famished all the time. There are days when i indulge past the 1200 but even then, for the most part i don't go over 2000.

                I always knew I was "unusual" !!! Then again, wine probably instantly disqualifies me from this lifestyle.

                1 Reply
                1. re: im_nomad

                  Yeah, 2000 seems pretty much within normal ranges for a lot of people, especially if you're a woman. But, then again, there are so many variables to what's appropriate -- your base metabolism, your activity level, etc. Perhaps for Americans they should rename this calorie restriction diet to a normal diet for the rest of the world. I really think portion sizes in America are really large compared to a lot of other countries.

                2. As someone who's been learning about the CRON method for some years now, I'd like to direct anyone with questions to the CR Society discussion archives at


                  There are also a number of CRON bloggers out there. The most prominent is April, whose blog is at


                  April also links to a number of the other CRON blogs.

                  As most CRONies put it, the bottom line is "calories, calories, calories." The number of calories an animal consumes correlates directly with its lifespan. But the ON (optimal nutrition) part is obviously critical as well. Some nutritional deficiencies will reduce quality of life, and others will actually reduce lifespan. Some CRONies also like to tack on an OS, as in CRONOS. The OS stands for "optimal supplementation." Certain supplements may offer some benefits, but are not a replacement for optimal nutrition. Nutritional science is not at all advanced enough for us to be able to eat crap, or eat insufficiently, and pop pills.

                  CRON practice and enjoyment of food are not mutually exclusive. You tend to enjoy the foods you habitually eat. If you are used to consuming a lot of fresh vegetables, lean protein sources, perhaps dairy, "good" fats, some fruits, and some beans/grains/legumes, you will probably enjoy them.

                  The level of calorie reduction varies from person to person. There are older women on CRON who eat around 1000-1100 calories per day, and younger men on CRON who eat around 2000 per day.

                  The key, in every case, is to minimize calories while maximizing both length of life and quality of life. Apart from the desire to usually keep calories low and nutrition high, there is nothing stopping a CRONie from having a piece of cake, a bun, a cheeseburger, or a bag of Cheetos every once in a while. Some CRONies choose never to have these foods. Others will have a small quantity of junk food once a month or once a week. The main concern is that the calories be accounted for, so that you don't accidentally consume 500-1000 calories worth of cake if you were only intending to have 300.

                  Some CRONies drink alcohol. Many of them have a daily glass of red wine with dinner. Again, the main concern is that the calories must be counted and the amounts shouldn't regularly exceed sensible levels.

                  Yes, the nutritional tracking does take some time. For experienced CRONies, tracking may take only about five minutes a day (no, I'm not exaggerating). For new CRONies, getting a feel for the nutritional values and calorie counts of the foods they often eat can be time-consuming. The first month or two may be difficult.

                  The question about every-other-day levels of eating hasn't really been fully resolved yet. Meal frequencies, and types of food consumed together at meals, are frequent topics of discussion among CRONies.

                  Yes, it is an odd hobby. Yes, it requires a knack for analytical thinking and some organizational skills. Yes, for many it also requires that you spend more money, not less, on your food. High-quality food is not cheap. Yes, it's true that you can't decide on a whim to have fish with beurre blanc, or fried chicken wings, or a big burger for dinner.

                  Like any other eating style, CRON is not a disorder unless it impairs your health or quality of life.

                  If CRON itself impairs your health, then you're obviously not properly practicing the "optimal nutrition" bit, either by not consuming enough calories or by consuming non-nutritious calories. If it impairs your quality of life, then of course you shouldn't be doing CRON.

                  No one should engage in long-term habits that make them less happy or less healthy!

                  For the record, most CRONies report being pretty happy with their eating style and their quality of life. Many of them maintain very regular check-up regimens with a supervising doctor, to track things like cholesterol counts, blood pressure, blood cell counts, body temperature, bone density, etc.

                  There are certainly downsides. Some CRONies report that they get cold more easily due to their slender builds. Some (not all) male CRONies experience a drop in libido. (Female CRONies often report an increase in sex desire.) Injuries and surgery require an increase in calorie levels so that the body can shift out of maintenance, and into active repair mode. Extended family members and friends may become resentful of new eating habits -- any of you who have tried to change your eating habits in any way at all may be familiar with this.

                  To tie this back into Chowhound -- it is certainly possible to both enjoy your food and to practice CRON. You probably won't be eating fatty pork belly or gnocchi or white bread very often if you're on CRON, but plenty of good things remain on the daily menu: sashimi, composed salads, good oils, fresh berries, a large variety of vegetables and fruits, braised meats, yogurt, some cheeses, nuts, avocadoes, perhaps beans/legumes, oatmeal, teas and coffees...

                  1. In the experiments, the underfed rats lived longer but I'd be willing to bet $1 that they were not happy rats. I wonder if they were short tempered, fought each other more.

                    4 Replies
                    1. re: walker

                      I believe the rats were too tired to fight...

                      1. re: KTinNYC

                        Actually, studies showed that with the right amount of calories, they were more energetic and athletic

                        1. re: takadi

                          Totally makes sense. What happens to most of us after a big meal like Thanksgiving? We all want to go to sleep.

                          To me, 2000 calories still seems a bit high to be considered calorie restriction, especially considering how sedentary a lot of Americans are.

                          1. re: Miss Needle

                            It might be. 2000 calories seems to be a good amount for "beginners" who don't want to graduate to eating a piece of lettuce for the rest of their lives.