Calorie Restriction Explained

Calorie restriction or caloric restriction, usually abbreviated to CR, is a strategy proven to extend healthy, average, and maximum life span in many short lived species, including mice and rats, and at least healthy and average life span in primates. In research papers it is more usually called dietary restriction, abbreviated to DR, and rodent studies conducted over the past 20 years have reliably demonstrated up to a 40% increase in maximum life span through life-long DR.

These benefits to health and longevity have been shown in animal studies to roughly scale with the degree of calorie restriction imposed, but there is good reason to believe that any gain in primate (and especially human) life span through CR is much more modest than that observed in mice. The calorie restriction response exists in near all species tested to date, and probably evolved very early in the history of life on Earth as a way to increase the chances of surviving seasonal famines or other periodic shortages. Such shortages are the same length whether you are a mouse living a few years or a man living for decades, but for the mouse a season is a much greater fraction of a life span, and thus only the mouse evolved dramatic extension of life in response to famine.

While human calorie restriction doesn't have the same impact on life span, it does provide numerous benefits, such as a greatly lowered risk for most degenerative conditions of aging, and improved measures of health. In recent years, human studies of long-term and short-term calorie restriction have comprehensively demonstrated these benefits. Many researchers believe that the evidence to date shows the practice of CR will in fact extend the healthy human life span, but there simply isn't enough data yet to pin down the effects on life expectancy. It is plausible that they are at least as good as those resulting from exercise. If so, it could mean a difference of 5-10 years of life.

Calorie Restriction Research

The beneficial effects of CR in laboratory animals have been known for more than 80 years, but only in the past 15 years has an appreciable level of funding and attention been given to this field. Human studies such as CALERIE have been underway for years and many research groups are digging into the operating details of cells and metabolism to firstly explain how the CR response works to extend life, and secondly to try to produce treatments that can mimic this effect. So far a great deal has been learned, but little headway has been made towards calorie restriction mimetic therapies. The genes and processes that control metabolism are notoriously complex, and scientists do not yet have a complete understanding of even this one narrow slice of the bigger picture.

So what is known at present? Loss of visceral fat tissue should be mentioned in the context of CR, as we all know that if you eat fewer calories, you will tend to slim down. A mountain of research indicates that carrying excess body fat is harmful to your long term health in many different ways. Even modest levels of excess weight increases the risk of later suffering common age-related conditions such as diabetes, cancer, and Alzheimer's, with one of the contributing factors being the relationship between fat cells and chronic inflammation. It is no exaggeration to say that if you are overweight, you will have a shorter, less healthy life. This is repeated by the scientific community in study after study. Given all of this, it is plausible that some portion of the health benefits of CR stem from the accompanying loss of fat tissue, although biochemical research indicates that there is clearly more than just that going on under the hood. CR is also creating a variety of positive changes in the controlling mechanisms of metabolism.

For example, it appears that CR provides a boost to the processes of autophagy. Autophagy is the way in which cells remove damaged components in order to recycle the materials into new replacement parts. Several lines of research indicate specific types of damaged cellular components left to cause problems over time contribute to age-related decline and damage inflicted upon the rest of your body's machinery. A greater level of autophagy may help reduce this contribution to the aging process, and thereby extend life.

Practicing Calorie Restriction

How to get started on CR? Fortunately it isn't hard: a wealth of information and many, many starting points exist out there. A restricted diet of this sort aims to reduce the intake of calories to a level 20-40% lower than is typical, while still providing all the necessary nutrients and vitamins. With this in mind, CR is sometimes called "calorie restriction with optimal nutrition" or CRON, and its practitioners have accumulated many years of experience in how best to achieve this end. Good books and a supportive community exist to help newcomers adopt the best practices for CR in humans. Mild CR can be as easy as adopting a much healthier diet, taking a few supplements and not eating snacks. You might find the following path useful.

Obtain a Copy of "The Longevity Diet: Discover Calorie Restriction"

This book is a very good, easy introduction to the principles and simple ideas behind calorie restriction. Beyond that, it is a practical guide that will help you over a lot of the early pitfalls. It handily answers the "what exactly is it I eat?" question and offers some great tips for new practitioners.

Practice Eating a Better Diet First

While waiting for your book to arrive, you can start to shift your diet in preparation. Have a look at this resource for a class of diets known as "paleodiets":

The selling point of paleodiets is that they replicate the hunter/gatherer diet of our ancestors, and are therefore better for us. This is not an argument advocated here at all, but trying out a paleodiet is a great introduction to many of the strategies you'll adopt while on a calorie restriction diet. One thing that you will find out quite early on in your journey into calorie restriction is that you have to stop eating any significant amount of highly processed, rich, modern foods. These items are delicious, but heavy in calories and light in nutritional value.

In the US, you can walk into any corner store and eat 1500 Kcal of junk food (chips, chocolate, and so forth) at a cost of $10. You'll be hungry again a few hours later. That same $10 could feed you for two days if you buy vegetables, rice, and beans. You could eat 1500 Kcal each day and hardly be hungry at all. These two examples lie at the opposite ends of the spectrum, but most people eat many more "empty calories" (calories that do not provide vitamins and essential micronutrients) than they should. Adopting a paleodiet for a while is an easy way to start thinking seriously about what you eat, how you cook, and how you can better organize your eating habits. It's a smaller and more manageable step than leaping straight into calorie restriction.

If you were eating an unhealthy diet, you will probably notice the benefits of healthy eating within a few weeks. Your palate will become more sensitive to subtle tastes, you'll need less sleep, feel more alert, and mood swings will be diminished. Much of this stems from cutting the intake of processed sugars.

Pay Attention to Calories

Counting calories is a good thing, and something that you have to pay attention to. Your body will let you eat far more than is good for you, so your brain is going to have to take over managing the process. Almost everything you buy from the grocery or supermarket has the calorie content listed on the packet.

Note that most manufacturers list calorie content by portion, and that even a lowly bar of chocolate usually has two portions. Marketing departments don't like the number of calories to be too high, as people won't buy it ... so they'll just divide the product into more portions with a lower calorie count per portion. Sneaky! Most foods have more calories than you might think. You can recognize the new practitioners of calorie restriction at the supermarket: they'll be the ones looking at many different product packages and muttering "wow, I had no idea!"

For foods like apples, rice, loose vegetables, and so forth, you will need a book of calorie values. Recent editions tend to contain (fairly horrifying) values for fast foods as well as the more usual suspects. You might try the well regarded "Food Values of Portions Commonly Used":

If you'd prefer an online reference, NutritionData provides a wealth of searchable information on various foods:

Remember the Supplements

You should always take a good multivitamin supplement when practicing calorie restriction. In theory it's perfectly possible to obtain all the vitamins and micronutrients you need from your food. In practice, for most people living busy, working lives, this just isn't going to happen. Remember to take your supplements.

The Water Trick

Many people find it easy to mistake low-level thirst for low-level hunger. A very helpful tactic for those practicing calorie restriction is to drink a glass of water when first feeling hungry. If you are still hungry twenty minutes later, then maybe it's time to think about eating. Half the time, you were just thirsty, however.

If You Have Questions, Ask!

There is a large and very helpful calorie restriction community out there. You might start to become involved by joining the CR Society mailing lists and feel free to speak out. These folks have plenty of advice and helpful hints for newcomers. Everyone was new to calorie restriction at some point in the past, and there are no stupid questions.

It's Just a Diet, So Relax

Too many people approach diets in an all-or-nothing way. They slip up or eat poorly one day, become stressed, and abandon the diet entirely in frustration. The key to health through diet is a relaxed attitude. If you slip up, let it go. Keep at it, do better next time, and work on the average. Remember that a diet is simply a tool to make you healthier, and thus enable you to keep up with what you enjoy in life.

The Future of Your Longevity

If you've read this far, you are probably interested in living a longer, healthier life. Calorie restriction is still the only widely available tool in the longevity toolkit today, which, when you stop to think about it, is a rather sorry state of affairs. This will not always be the case, however, as medical science and biotechnology are advancing ever onward. It is worth remembering that as time progresses your remaining healthy life span is determined ever less by how well you maintain your health, and ever more by the rate of progress in regenerative medicine, work aimed at repairing the accumulated cellular damage that is the root cause of all age-related disease and infirmity.

You should look into calorie restriction today, but also consider the long-term view: supporting medical research into extending and restoring health is just as important, and it will become ever more important as time goes on that you made some effort to help the development of better longevity medicine.

Last updated: May 20th, 2014.


Very interesting. I did not know about this.

Posted by: Andualem Anteneh at January 3rd, 2011 11:33 PM

looks a little daunting for a first timer, but will give it my best effort..

Posted by: David at January 17th, 2011 1:30 PM

I am curious as to your thoughts on the idea of "negative calorie" foods, if they might apply to CR and if there might be a way to prove or disprove it. I've done searches and bought an ebook but have found no proof for or against the idea. Seems to me there should be some foods that require more calories to digest than they can supply to the body.

Posted by: dale at January 26th, 2011 5:25 PM

@dale: the triggers for the benefits of CR apparently involve, amongst other things, sensing food, levels of amino acids in the diet, and to some degree the level of fat tissue in the body. Flies can gain most of the benefits of a CR diet through a low methionine diet at normal calorie levels, for example.

Negative calorie foods may or may not exist, and you're certainly going to have trouble finding reputable information out there.

But CR is about absolute calorie intake, not net calories in minus calories burned. Athletes on high calorie diets may be pretty healthy because they're exercising to burn it all off, but they're not practicing CR nor are they in any way gaining the benefits of CR.

Posted by: Reason at January 26th, 2011 5:39 PM

I've found intermitent fasting (IF) to be the easiest and quiet enjoyable. I fast three days a week--- Monday, Tuesday and Thursday.... I've done this for a year and half and actually look forward to fast days. on the days I do eat, it's sensible without restrictions (my stomach shrinks from the days of fasting, so you really can't eat crazy. I love my IF diet!

Posted by: mory at May 8th, 2011 8:02 PM

I have know about CR for a very long time, but only recently decided to take it on as a lifestyle. It's only been about 2 weeks, but I'm loving it already.

Posted by: cron living at June 22nd, 2011 9:05 PM

Hello from Australia. I am a 50 year old male who has been on a CR diet for the past 20 years. I sort of fell into it without initially realizing the health benefits. At age 30 I carried out a 50 day liquids-only hunger strike to protest rainforest destruction. My appetite never returned, and a doctor told me at the time that we have two appetites - a time dependent appetite and a smell dependent appetite. He said I had lost my time-dependent appetite, which is like a 'habit-based' appetite. For example at lunch time your body tells you that you are hungry as it is in the habit of being fed at that time - not because you have a sudden need for an infusion of nutrients. Anyway, I digress. Back to the CR diet. I generally eat one small vegetarian meal in the early evening, although if I really feel like meat I will eat a small amount. I usually just have coffee for breakfast and lunch, which keeps me regular, protects me against lower bowel cancer, and is a liver tonic. At 50 I weigh the same as in High School (around 67kg), have slightly low blood pressure, perfect cholesterol levels, and no signs of mid-life age related diseases. My older brother at 52 has eaten a normal western diet all his life and is 'slightly obese', pre-diabetic, and has high cholesterol and high blood pressure. As we are very close genetically I believe these differences in our health indicators are totally due to diet.

Posted by: Brett Pritchard at July 5th, 2011 12:08 AM

I've been very interested in CR myself, but I think this article fails to even list the potential downsides well enough. I've put together a little article myself with many references to scientific articles, in case anyone wanted to look into it further.

Posted by: mrnuts at November 5th, 2011 3:54 AM

The whole idea of CR makes perfect sense really. The less we eat, the less the body has to work to expel all the waste products and the more efficient the body becomes at utilizing the energy that is consumed. The more a car is driven, the faster it will break down, especially if it runs on dirty fuel! I am keen to try this diet. Just have to get rid of my sweet tooth.

Posted by: Simon at December 27th, 2011 3:39 AM

That sweet tooth has a lot to answer for, doesn't IT?

Posted by: Michael at December 29th, 2011 11:40 PM

I have a question about CR, it would nice if one of the moderators here could address it whenever possible. I'm wondering if CR can be regarded as the same as having a low percentage of body fat. Because I don't restrict my diet at all, but through exercise and healthy eating I have a low BMI. I have some of the same side-effects of CR, such as cold sensitivity and low blood pressure, and I would (obviously) love to have some of the benefits as well. Many athletes have excessively low BMIs, much lower than mine, and don't restrict their caloric intake at all. In fact, in order to maintain great strength and muscle mass, they're forced to eat more. So what exactly is it: low intake or low fat?

Posted by: Amy at January 8th, 2012 8:12 PM

To the comment moderator: nevermind. I've read through the website a little more and have found the answer to my previous question. From what I understand, lower body fat aids in a healthier immune system, but that's not the whole picture.

Posted by: Amy at January 8th, 2012 8:15 PM

@Amy: Short answer: it's intake, but lower levels of visceral fat have their own benefits.

The benefits of calorie restriction are likely a combination of effects, of which lower levels of visceral fat is but one (and probably a minor one). Visceral fat is certainly bad for you in excess:

Exercise improves healthy longevity through a separate collection of mechanisms, with a small amount of overlap with calorie restriction - such as the lower levels of fat, and increased autophagy.

The trigger for metabolic and other biochemical changes brought on by calorie restriction is largely reduced intake of dietary protein methionine:

Posted by: Reason at January 8th, 2012 8:21 PM

I have an over active gallbladder. The doctors wanted to remove it but I told them I would try to control my symptoms with diet. Tried several diet strategies and the one that works is eating one meal a day. It turns out I backed into CR in the process. That lead me to this web site. It works for me. I’ve never felt better.

Posted by: Edward at March 3rd, 2012 4:13 PM

This is a good introduction to CR. I am pre-diabetic owing to long term chemo as a child. I'm doing the CSIRO total wellbeing diet at the moment, which is brilliant, as it is nutritionally balanced, and am able to cut calories significantly without feeling hungry and getting too many sugar swings. I suppose this is a watered-down version of CR. Feeling so much better by eating less.

Posted by: Teresa Steele at March 15th, 2012 6:38 AM

Well, I had heard of calorie restriction before and always thought that it was not for me. I would love to extend my life but not enough to cut out good eating; I am a bit of a gourmand. Anyway, I recently discovered that I had become lactose intolerant and shortly afterwards stopped being able to digest wheat. I don't think it is anything to worry about because these two complaints are things that my mother and brother have been complaining of for years so I suppose it was just a matter of time.

I now discover that I can almost eat nothing and am largely living on oat clusters and berries with lactofree in the morning and sushi for lunch with a possible wheat free sandwich at night. Since I stopped eating wheat I have found that I no longer get food cravings. I used to just stuff myself but I guess I must be better able to absorb my nutrition without the wheat in my diet.

The thing that brought me to this site was a websearch because I had noticed that I was regularly sleeping for less then seven or six hours a night now. I had forgotten about CR so I was pleasantly surprised to discover I could expect extended lifespan as well. I do not go in for the constant calorie counting but I reckon as I lost 5 pounds in the last 10 days I must be on a CR diet. I have always paid attention to nutrition so although I probably could make an effort to eat a little more healthily I am certainly not eating rubbish.

It is odd that what I had once considered as too difficult and unpleasant to even try I have had imposed on me by nature and is actually not even all that tricky in practice.

Posted by: Ro Atkinson at April 19th, 2012 6:10 AM

I'm 81.I have always kept slim,weighing 10st 4lb as I did at eighteen. I reduced my 18-1900 cals/day to 1200 without problems a year ago. Not hungry or cold. Intensive Interval training regime. Weight still 10.4 surprisingly. Aim not to live for ever but to die suddenly,unexpectedly,and in the best of health!
BP av 112/68 resting pulse 9bpm. fasting blood sugar 86.Total cholesterol <3.9. Never had therapeutic or recreational drugs.Last doctor visit, apart from compulsorary pilot medical( yes )1970.

I reckon CR is easy and very beneficial. I certainly feel fine on it, and slight arthritic rwinges have disappeared.

Posted by: simon at April 27th, 2012 11:11 AM

I do think there is something to the CR diet - I have also fasted in my life and I know the benefits of healing that can be accomplished when you let your digestive system rest. Animals fast quite naturally when they are not sick. Humans should do the same - it's in the Bible as well to fast. Doctor supervised, fasting clinics can be found in Europe but books on fasting are very fascinating to read and the few times I have put myself on a long fast, I could tell that there was a healing process of the mind, body and soul. Good luck with your endeavours - you are on the right track.

Posted by: Dana Montez at May 14th, 2012 8:26 AM

I am a 62 year old male who just started a CR diet. My eating habits have steadily improved over the years as I have become more sensitive to foods that are bad for my health. But before CR, I was only able to maintain my weight, not lose weight. I have been on the CR diet for 6 weeks and have lost 6 pounds. I eat a healthy breakfast and lunch, but try to limit dinner to a healthy snack such as fruit or some vegetables. I am not too concerned about getting enough nutrition as I have been a supplement fanatic for several years. I am never sick. My activity level varies from day to day. My biggest problem is that I get hungry easily. I want to reduce my body fat and get down to a weight I can maintain. I am at 20% body fat. What is a safe range for body fat? I am hoping that once I reach my weight goal, the hunger will be easily managed.

Posted by: Michael Kelly at July 29th, 2012 8:20 AM

we are using calorie restruction,it works good for me,however my wife says it makes her tired she has quit carbohobrates,can you advise us why and what to do?

Posted by: richard hughes at August 6th, 2012 11:52 AM

I am planning to start CR but am obese at the moment (30% fat) i have a fascination with data and would like to participate in or start an experiment that would be useful to others. Does anyone know of individuals or groups running or supporting CR experiments that we can join or be guided by?

Posted by: Jolyon at September 3rd, 2012 1:06 AM

Does anyone know go any good sites that have recent articles on CR? any recent studies or evidence out there that i can read. I think the CR diet is the most logical and i have started to follow it, I am just sick of trying to defend myself to people that think i am an idiot for "not eating enough" or "you need to have some bad food" etc etc I'm sure you have all heard it before, having something to defend myself with would be good!

Posted by: Chloe at November 13th, 2012 10:55 PM

I have tried calorie restricting diets to lose weight, but I was far too hungry to carry on with them, then I saw a programe on television about alternate fasting. I tried it, but couldn't cope with restricting myself to only 500 calories as I'm a piggy and like my food too much.

I decided to restrict my calorie intake for two days a week to 1,000 calories on Mondays and Thursdays as I couldn't handle two consecutive days with food restrictions. It worked. I have lost three pounds already in less than two weeks and have only half a pound more to lose. I hope that once gaining my target weight I need only restrict my calories for one day a week.

My memory has improved and I have more energy than before. The strange thing is that on the days after eating only 1,000 calories I had four meals and I was still losing weight. It's as if my body went into burn up mode. I intend to stick with it as it's successful and means I can eat normally for five days.

Posted by: Angel at January 19th, 2013 3:22 PM

Hasn't research now revealed that calorie restriction doesn't extend lifespan in primates?

Posted by: Libby at September 11th, 2013 10:59 PM

I have been hearing and reading about CR for some time.Some of the initial research has been debunked; however like most eating plans, it has some merit. I see no reason to take it to extremes however.
As far as I can see, one of the most important things is to eat enough roughage so that you poo really regularly. I have seen bowel cancer in relatives and it isn't pretty. I believe some CR believers eat vast quantities of vegetables and fruit, which makes sense.
On the subject of supplements - personally I can't afford them, they are really expensive, so I do try to get as much nourishment from my diet as I can.
I do know one person who fasts regularly and does CR,but does no exercise at all. Yes he is thin, but no muscle tone to speak of. I think you need to work out at least moderately for optimum health.

Posted by: Ros at November 12th, 2013 11:08 PM

I think CR is extreme, & a club for those who want to be bone thin & willing to work at getting the correct balance of nutrients & hormones in their body.
I do believe that the long standing doctor suggested balance of a number of nutrient calories should be determined by the persons height,skeletal structure,
genetics & active life style.
With this I've always know that we should eat only what we need ( not less ),
but stop when you know you are no longer hungry.
Unfortunately there have been too many years that restraurants piled huge amounts of food on a plate & people got used to this, which is so unhealthy.
Lean is better, but not CR which is too low in calories for optimal body functions is my opinion. Calories should be nutrient densse & you will eat less naturally.

Posted by: Robin at January 12th, 2014 4:19 PM


Do you know if I have to be consistent with my CR diet? For example, half my week is split up into "exercise days" with normal caloric intake, and the other half of the week is "CR days" where I do not exercise for the day but try to intake less calories. And they are split up as every other day such as: Monday (exercise), Tuesday (CR), Wednesday (exercise), ect.

My question is whether I have to do CR everyday to reap the benefits versus what I am doing now? It is pretty hard to run a few miles on the "exercise days" and then go home and starve myself.. Otherwise, my "CR days" consist of me doing my work on the computer and not getting up and moving around if not necessary. I am wasting my time with my current regiment?

Posted by: Donald at January 29th, 2014 4:11 PM

@Donald: No-one knows the definitive answer to that and many similar questions. You might look at posts on intermittent fasting to see where the boundaries of the known lie for this sort of thing:

Otherwise, you might take these questions to the Calorie Restriction Society mailing lists - they've spent many years chewing over these and other questions, and will no doubt be able to provide some helpful insight and references.

Posted by: Reason at January 29th, 2014 4:25 PM


What do you do if you are physically active and want to try out CR?
I also find that when I exert my brain working on a project, design, piece of hardware, calculations, etc, it makes me noticeably more hungry than watching a documentary. The brain is a carb crunching powerhouse that needs to be accounted for.

Do you just add the calories you burn or something similar? I can tell you a 90 minute football/soccer match or a 10km run will drain your energy.

I believe being healthy and staying younger is a combination of moderate exercise with the occasional intense day, good diet with lots of fruits , veggies and antioxidants to protect error-free DNA replication and a positive state of mind and social support.

Not letting things stress you and having goals and something to do is also very important.

**** For the people that are trying to lose weight with a diet alone... Do some exercise! Our bodies are meant to move. Then instead of 6 pounds in 6 weeks you'll see 2 to 3 times (the move you have the faster it falls) that even with light to moderate exercise. It also gets you a sense of achievement that becomes a powerful motivator.

Posted by: OVi at May 6th, 2014 8:10 AM

I have a big question: when you say calorie restriction, do you mean count my calories and eat a normal,heathy amount everyday like - say 1000; or, do you mean reduce caloric intake and be starved - say 600 a day?

I have been counting calories for about a month and I feel very well; I find this to be the easiest diet I have ever one and not only am I losing weight, but I actually feel better.

What I do: I have five meals a day (9am, 1pm, 4pm, 7pm and 10pm); On each meal, I eat - give or take - 200 calories. I am very sedentary, so I don't believe I need more than 1000 calories a day to function. I try to eat healthy food but the cool thing about counting calories is that, if healthy food is not available, I can still count calories and not disturb my diet much.

My question is: am I doing the CR thing? Am I doing it wrong?

Please help me!

Thank you all!

Posted by: María at November 20th, 2014 9:56 AM

@María: I suggest you sign up for the CR Society email list and ask there: that is the sort of long form question that they are very good with. You should find it easy to have a productive, educational discussion on the day to day practicalities of CR with the folk there.

Posted by: Reason at November 20th, 2014 1:54 PM

At some point you have to ask yourself what do you enjoy in life and how much is that worth to you? If I am going to miss out on eating (and on overeating if I want) great food on all social events in my life, be it family or friends how much worth it is CR diet? If it adds 4 years to my life, which it very well could, but I missed on on life enjoyments along the way what good is it?

Life is short and we should be eat and live healthy, but my god, purposely restricting calories so I live few years longer at the expense of fully enjoying all that is offered, what good it is?

Posted by: voice of reason at December 11th, 2014 3:55 PM

When I was a kid I used to eat only a little,
now i am 25 and i just keept eating less than the average person,
I only eat two times a day, and eat less than the average person does,
I hardly get sick, and I'm in better shape than most people i know.(BMI 22,3 low body fat)

Posted by: Igor at December 28th, 2014 7:22 AM

voice of reason,

I follow CR and yes, I enjoy life and I enjoy the food that I eat. I had a plant based diet since I was a teenager so I'm fairly familiar with how my food choices affect the lives of animals and other people via environmental impact. About three years ago, I made a decision to make the most out of my calories besides sating hunger. The calories had to be 1. something I truly enjoy 2. in the company that I enjoy or 3. offer the most nutritional value. I prefer number 3 most of the time but occasionally 1 or 2. I enjoy a life of 1. being fit, 2. making the most bang out of my calories and my food bucks 3. extremely low cancer, heart disease, AL and dementia risk 4. more time on my hands for not cooking a complicated meal 5. longer lifespan for me to achieve all my wildest goals.

Posted by: A. Quach at January 5th, 2015 9:38 PM

Holy crap! I always knew in my gut (no pun intended) that consuming fatty, nutritionally low, processed foods were bad for the soul, but I never realized how much of a difference it makes! I'm 35 now and people mistake me for a teenager. I weigh substantially less than average, totally immune to all but the strongest super bugs and recover from injuries much faster than the average person.

The secret to this lifestyle is

1. do not eat processed food
2. do not consume sugar
3. consume large quantities of coffee, honey&ginger tea, and red wine

thats basically it, its so simple even a caveman could follow my diet!

I'm in a state of near starvation most of the time, but the hunger pains simply remind me I'm alive.

Posted by: Peter Pottinger at April 10th, 2015 4:29 PM

The only issue I have with this is the restriction on 'rich' foods. The more I read into this, and try it myself, the more I find that fat foods, from the right sources, actually don't make you fat at all. I've almost completely replaced all carbs and sugar (including whole grains) with animal fats, and I get most of my protein from high-fat sources, not legumes, and I rarely use vegetable oils. I tend to eat a lot less now and actually have lost weight since I've started doing this, about 3-4 years ago. I started with a BMI over 22 and I'm now around 19.1, and that was when I was running anywhere from 3-6 miles a day. Now I hardly ever work out (not intentionally), and I eat 3 eggs a day, a big glass of whole fat milk, at least one meat product, usually beef marrow broth, and I cook everything with butter or coconut oil. I physically feel a lot better, my hair is shinier, my skin is more supple, and I'm not as moody.

There's an interesting video posted on YouTube I watched recently that sort of talks about this, called "Part 10 Dietary Guidelines Press Conf-Dr. James Carlson begins", I encourage you to check it out.

Posted by: Amy at May 23rd, 2015 1:57 PM

Its funny because i always was an advocate of 2000cl a day. But to be honest some days i just dont feel the need to eat that much, somedays 800cl is fine. Latly i have been doing 2000 consitanly and never got hungry. It felt like i was eating for the sake of it, not for health. Now i think ill enjoy mild hunger and eat less, depending on how much i exert myself.

Posted by: crystal at February 5th, 2016 2:53 AM

The degree of exercise matters as well. DR success depends on getting enough calories to function; especially if one does heavy manual labor.
Working on farms, I noticed the farmers invariably had high-calorie diets. One reason the farmers I observed ate such rich foods was to save time: in summer they would work 12-15 hour days, and so they'd grab a meal and go.
Another reason was the farmers needed the 'lift' of a stimulating diet. Yet another was the fact that with their level of exertion, they could easily 'burn off' the calories. And in fact they could drink alcohol at night to help them sleep, without affecting their health-- at the age they were at the time. (Avg. age teens-fifties.)

Posted by: Alan Brooks at July 25th, 2016 6:12 PM

Is there a CR diet that provides the RDA of all known vitamins,minerals & essential fatty acids

Posted by: Peter Lindstrum at September 27th, 2016 2:15 AM

Informative article. Didn't knew even unbalanced calorie intake can cause severe health hazard. The article mentioned that one needs to follow diet plan to keep check on calorie intake, it would have been nice if I would have found more information through this article about how much calorie is adequate according to the individual's age.

Posted by: Adam Herrera at September 29th, 2016 8:02 AM

Restrição calória parece uma colocação aleatória. Autores mostram que a necessidade calorica diária de uma pessoa comum é de apenas 1200 cal/dia. Se se tomar com base a tabela americana de 2400 cal/dia é claro que a redução de 20 a 40% nem vai atingir o ideal, então o que é Redução Calórica de verdade? Eu aceito piamente a ideá de 1200 cal/dia então redução calorica seria comer apenas 1000 ou 900. Isso sim seria redução calorica verdadeira. Neste caso seria impossivel uma pessoa desenvolver alguma das doenças comuns que afetam a humanidade atualmente. Claro, que com isso sua longevidade cresceria muito...em termos de 50% e atingiria facilmente 130 anos. Mas a discussão está usando numero extratosférico como 500 anos... isso é um absurdo atual. Creio que levaremos alguns milênios para chegarmos lá.

Posted by: abilio bernardes da silva at October 6th, 2016 6:21 PM

What if I want to gain muscle?

I'm 6'0, 155lb and my "maintenance" caloric intake is about 2600 cals per day.

If I wanted to be 185lbs athletic and muscular, conventional science says i'd need to eat 5000 cals per day to get there, and 4000 cals per day to maintain it.

Is this why bodybuilders get heart attacks so young? Or is it just the steroids?

Related question: exercise is said to be anti-aging. What happens if you eat a lot of calories and burn them off athletically?

Are there any studies about this?

Posted by: Jorge at June 7th, 2017 9:13 PM

I was always a naturally small person weighing between 105 and 120 lbs.but 2 years ago I was put on a medication that caused me to gain 40 lbs in a few months.i got off the mess and quickly dropped 10 lbs.But that was it still chubby after a year off the mess .i have recently started a low calorie lifestyle consuming between 600 and 800 calories daily.i am making sure to have a high protein meal daily but I worry about vitamins and minerals I may be missing out on.i take an iron supplement and B12,magnesium,zinc and calcium.does anyone have any advice on what I may be missing or tips on how to stay healthy on this plan.after a month or so I'm going to increase my intake to 1000 new to this and would appreciate any advice

Posted by: Emily Dixon at July 11th, 2017 10:30 PM

I would like to ask Peter Pottinger ( Holy Crap ! )what else do you eat aside from lots of coffee, lemon & ginger tea and red wine ? Surely some fruit and veg ?

Posted by: Marie at November 2nd, 2017 12:16 PM

According to the 2017 book THE TELOMERE EFFECT, calorie restriction apparently does not work in HUMANS; instead, in the case of HUMANS, sugar restriction is the way to go.

Posted by: Charles Tandy at January 6th, 2018 11:40 AM

A good resource to lookup the caloric and nutritional content of various foods can be found at the USDA website:

Posted by: Jarod Rollins at January 2nd, 2019 7:54 AM

Reason, I'm not sure if you read our comments, but have you ever discussed the CALERIE trial's findings of adverse impact on bone mineral density?

CR (for those with little bodyfat) frankly never made sense to me, and this result is exactly what you'd expect when you take people already at healthy bodyweight levels and put them in prolonged calorie deficits. I think the risks of CR have been greatly underestimated for non-overweight practitioners.

Posted by: George Nieman at May 27th, 2022 2:05 PM
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