The Elusive Central CR Question

[JJeffreyBragg]

Getting started with CR has been an interesting and intriguing experience. Like many people, I first began calorie restriction by sheer instinct: fed up with being overweight, looking like an 8-months-pregnant old man , feeling tired most of the time, I just determined to lose some weight by amending my dietary habits, dropping certain high-calorie foods, and mostly just *eating less*. I started at an estimated 215 pounds (at the time I didn't even own a viable scale) around the beginning of last November. All through November and December I knew I was making progress but couldn't quantify it.

 

Then whilst researching the topics of weight loss, calories and the like on the Internet, I came across CR. I ordered the Delaney/Walford "The Longevity Diet" book through eBay and bought a decent scale. By then it was the 5th of January, I weighed 175 pounds and I began keeping a dietary journal and immediately thereafter, to count my calories, weigh myself twice daily, and record it all.

 

Over the last month's time I have read through the book several times and spent a lot of time trying to get a handle on CR strategy and numbers. I'm now comfortable with counting calories, although doing a nutritional breakdown and recording protein, fat, omega-3s, ORAC etc. are still things I have yet to address systematically. My diet has changed to favour things like blueberries, brussels sprouts, broccoli, beets and so on, mind you; I'm just not tracking it all numerically yet.

 

Frankly, before I lose myself in the detailed nutritional breakdown of my diet, I need to figure out "the elusive central CR question"! The book gives hints, the CR site does also, but I don't seem to have understood one simple, basic issue. Up to this point it didn't seem that urgent -- I knew I wanted to rid myself of all that belly flab so I just worked on that and improving the quality of my diet. No more 600-cal slices of chocolate cake, no more big dishes of chocolate ice cream late in the evening, no more 3-eggs-with-bacon-toast-and-hashbrowns breakfasts, forget the cheddar cheese, etc. Fortunately I already had a lot of good food habits along with the bad ones -- I love spelt, kamut, buckwheat and quinoa, enjoy fresh salads, like berries and avocadoes, enjoy fish, and so forth.

 

Okay, here's the question: when CR books, websites and people talk about calorie restriction, it is often in terms of a reduction by various given percentages of caloric intake. That's virtually intuitive, given the "CR" label of the discipline. But I have yet to see much general agreement concerning the caloric baseline from which CR is supposed to occur! I know what the conventional, government-approved received wisdom is respecting caloric allotment, as quoted in the book: (Table 4.1, page 71) Moderately active men of average size - 2,500 calories/day; Moderately active women of average size - 2,000 calories/day. That "standard wisdom" is characterised in the book thus: "these recommendations are extraordinarily high compared with the calorie intake of people on the Longevity Diet."

 

I'm committed to a combination of the Weight Watcher and Calorie Counter strategies; I don't have easy access to and cannot afford extensive biomarker assays. So on the basis of a month or so of recorded personal data I've tried to determine what my own personal point of caloric equilibrium must be: the caloric intake that should just balance the needs of basal metabolic rate plus calories burnt through physical activity. An online calculator (based on gender, age, weight and height) puts that point at a notional 2450 calories for me (I'm male, 67 y.o., 5'11", and now 160 lbs.) For the past nine days I was trying to get from 165 down to the 160 pound target I had set for myself; over those nine days my caloric intake averaged 826 cal/day; I lost about 4.6 pounds over that period. (Yes, I know that's too rapid; I just wanted to get there and have done with it.) For the 24-day period previous to that, I averaged 1080 cal/day and lost 7.2 pounds.

 

Now: applying the conventional generally-agreed average caloric value for body fat, I tried a rough calculation of caloric intake via food plus calories from burnt fat. For the recent 9-day period, I came up with a combined average value of 2615 calories/day; for the previous 24-day period, the average was 2130 calories/day. The mean of these two figures is 2372.5, not that far from the notional value of 2450 for a guy of my age, height and weight.

 

If CR means a reduction of 30% to 50% of what I used to eat (a figure which I cannot tie down too exactly, largely because I'm too chicken to go into the gruesome details of how many calories I used to knock back in a day), then probably I'm laughing. If it was ~3000 calories or more (which seems likely) I'd be looking at a CR allotment of 1500 to 2100 cal/day! But if I should be working from a baseline of 2450 (or 2372?) my allotment should be 1225 - 1715 cal/day -- or less.

 

At the moment I intend to shoot for a daily allotment of ~1250/day and see how that works out. What bothers me is wondering whether I'll be continuously losing body weight at these lower levels. Perhaps my body will eventually adjust and find equilibrium at a body weight somewhere between 130 and 150 pounds?

 

I wonder if some of the old hands here can clear up this confusion for me, particular with respect to *what reference baseline* constitutes the orthodox CR point of reference for percentile reduction of caloric allotment. I'm listening!

[JJeffreyBragg]

This evening I have a little more time to flesh out some of details omitted above. First of all, the notional caloric value for body fat: I used the conventional 3500cal/lb. I'm aware that there is a lot of potential variability there, but if one has to pick a value for calculation, that one seems most commonly in use. (In any case, one shouldn't expect the maths to work out too precisely in this sort of thing as there are too many potential variabilities and inaccuracies involved: inaccurate assessment of portion size, inaccurate nutritional data for specific products, errors and omissions, daily variations in hydration and elimination, variable digestibility, etc.)

 

I feel that the present sales-pitch book (i.e., the Delaney/Walford) could use a new edition, with a view to clearing up some of the confusion. Just for a couple of examples, several different views of what is "fast" versus "slow" weight loss are presented -- wildly different. "JW" says "My weight didn't fall that much at first, it took about six weeks to drop down to 172 pounds from 206 pounds" -- !!! OTOH, Peter Voss says, "I lost weight slowly, not more than one pound per month." In general, the personal examples given are so strikingly varied that it can be difficult for the newbie to decide just what the typical or orthodox practice of CR looks like. Not that there's necessarily anything wrong with all these personal variations, but it might be helpful to indicate some sort of standard practice, thereby giving beginners a clear idea of where to start. So much effort has been put into explaining the details of human nutrition -- and rightly so, since there appears to be rather little general public understanding of those details -- that the job of presenting a clear CR model has perhaps not been positioned front and centre. I would also like to see the caloric value tables for various foods and food groups expanded yet further; inevitably these tables are heavily used for reference by the newbie, yet too many items seem to be missing -- kiwi fruit, zucchini, ginger root, e.g.

 

Finally perhaps I should clarify that I know it's early days yet for me with CR, I'm still struggling to discover what it all means for me, and I know that much will change. It's changing even now, as I've reached my initial preliminary target weight and, as indicated in the previous post, I'm now trying to discover an equilibrium-point caloric allotment for the next phase of all this, in which I'll probably continue to lose weight but much more slowly. After all, from a BMI of ~30 I've come down to a relatively normal 22.3; many CR practitioners, I'm sure, are lower than that on the BMI scale. Peter Voss, seven years into the lifestyle (in the book) says he weighed 155 pounds when he began but doesn't state his present weight -- yet tells us that 1800-1850 calories is his maintenance level for <5% body fat. I'm pretty sure that if I returned to that high a caloric allotment I'd immediately start to regain body weight, yet from the sound of things he's basically a smaller person than I. Obviously I need a better handle on caloric allotment.

 

Meanwhile, I FEEL SO MUCH BETTER! Today after several weeks of fairly close confinement to home in winter weather conditions of -18C to -28C with semi-constant light snowfall, the temperature shot up to -5C, the sun shone, and I took a walk with my favourite dog. Normally during the past few years those walks haven't been much more than a quarter to half a mile, but today I kept up a brisk walking pace for forty-five minutes and must have gone at least three miles! Heart rate in mid-walk was only about 60. Obviously the body LIKES CR! I'm feeling definitely more energetic and experiencing small waves of euphoria and wellbeing such as I haven't known for many years. I feel that I'm definitely onto something here, which is why I'm anxious to understand the practice better, as well as the principles.

[keithsct]

Jeffery, First, I'm glad that you've had some success with your first CR experiences. It's important to eat a balanced diet of many different foods. With respect to the question about how to determine where the appropriate level is, really each person has to figure it out for themselves. It varies a lot. Some fairly large people can eat 1000 calories and get what they need out of it. Some smaller people find it difficult to go lower than 2000 calories. There is no real great advice to give here. Just trial and error. Second, you really have to spend the time running the numbers on your diet and make sure that you're getting all the nutrients you need. Without this you'll eventually get sick once your body runs out of stored nutrients to use. The most important scale is the food scale in your kitchen, not the one under your heels. Nothing will end your CR experiments faster than a nutrient deficiency disease. Sometimes the effects can be permanent, so do yourself a favor and make sure you're getting all the required nutrients.

 

Even more important than the weight is the constellation of numbers that the medical tests tell. When you're on CR, your blood pressure drops along with body temperature, pulse rate, bad cholesterol numbers, inflammation markers, average blood sugar, thyroid hormones, blood count levels etc. Good cholesterol, energy for daily tasks, exercise performance and time between getting sick from colds and flu should all increase. I find it's a good motivator to measure these numbers and know you're on the right track.

 

One more quick point: Stop reducing weight when you get to a BMI of 18.5. After that, you'll be losing muscle tissue which is really hard to replace at your age. Also many people who get into trouble with a CR diet goes below 18.5 BMI.

 

For numerology here's my experience: I slowly gained weight from 160 in early adulthood to a peak of 203 lbs at age 35. I was sick and slow. I exercised a whole bunch and found I could push my weight down to 185 lbs and it would go down no further. Even at that weight, I was still sick and slow. Once I discovered CRON at age 43, my weight dropped from 185 to 155 lbs over a period of 6 months and stayed there for about 3 1/2 years. For me 155 is a BMI of 21. At max my BMI was about 24.9. I found that I could achieve this all with a diet of 1750 calories. My current weight is 161 lbs and I'm working my way back down to 155 again after breaking a couple of ribs and gaining some weight during recovery.

 

Keep on with it and maybe we'll see you at the CRSociety meeting this summer in California, if you feel like travelling.

[JJeffreyBragg]

Jeffery, First, I'm glad that you've had some success with your first CR experiences. It's important to eat a balanced diet of many different foods. With respect to the question about how to determine where the appropriate level is, really each person has to figure it out for themselves. It varies a lot. Some fairly large people can eat 1000 calories and get what they need out of it. Some smaller people find it difficult to go lower than 2000 calories. There is no real great advice to give here. Just trial and error. Second, you really have to spend the time running the numbers on your diet and make sure that you're getting all the nutrients you need. Without this you'll eventually get sick once your body runs out of stored nutrients to use. The most important scale is the food scale in your kitchen, not the one under your heels. Nothing will end your CR experiments faster than a nutrient deficiency disease. Sometimes the effects can be permanent, so do yourself a favor and make sure you're getting all the required nutrients.

 

I fully intend to monitor specific nutrients as I gain skill and familiarity with this. It has been a giant step for me just to start counting calories seriously and I'm still struggling to get that right; I don't want to take on too many unfamiliar tasks at once. At the moment I'm quite certain that I'm getting more ORAC foods than I ever have before (as well as more omega-3 sources), as I've added several that were not previously part of my normal diet and upped my intake frequency of others. Back in the 1980s I was a vegetarian for awhile, so I'm pretty conscious of potential nutritional deficiencies; in fact, that's why I'm not a vegetarian now -- it's a lot easier to ensure amino acid balance if one consumes modest amounts of flesh, fish, poultry, eggs and dairy products. Vegans are just asking for problems unless they undertake serious study of nutritional balancing, which is one reason why it makes me pretty nervous to see folks routinely attempting to associate CR *and* vegan practice.

 

I'm perplexed about this CR baseline question, though! To write a book about calorie restriction, making frequent reference to percentile reductions, whilst never clearly specifying the baseline or starting point for such reductions seems somewhat strange to me. I note that you haven't dealt with that part of my question either, Keith. I -- naively, perhaps -- just assumed that the old hands would know what defined the take-off point for CR; surely Dr. Walford must have addressed that issue at some point. (I've ordered "Beyond the 120-year Diet" but haven't received it yet.) There are only a few possible definitions for it: (1) the standard nutritional recommended daily intake as published on government and other websites as adjusted for gender, age, height and body weight, (2) the individual's pre-CR normal daily caloric intake, (3) the individual's body-weight equilibrium point of caloric intake -- I would say those are probably the three main contenders, but those three are far from identical in most cases. I think this is an important issue, particularly for "serious" or "extreme" CR practitioners.

 

 

One more quick point: Stop reducing weight when you get to a BMI of 18.5. After that, you'll be losing muscle tissue which is really hard to replace at your age. Also many people who get into trouble with a CR diet goes below 18.5 BMI.

 

Thanks for good advice. I had already surmised as much. You are entirely correct that at my age the last thing I would wish to do would be to lose muscle or bone mass. (In fact I'm considering joining a local fitness centre in order to resume doing resistance work with free weights, something I did a bit of several decades ago.) In any case, I think I'd start to panic long before my weight hit 133 pounds (which for my 5'11" frame would be 18.5 BMI). It is largely due to the potential for continued steady weight loss that I'm concerned to discover what the take-off point for CR percentile levels should be. I have, of course, read the parts of the Delaney/Walford book that discuss "set point" but found the discussion less than satisfactory. I can remember various points in my life when my accustomed body weight was 164 lbs, 170 lbs, 180 lbs, and 200 lbs. And the further back I seek to pin it down the less certain I seem to be. I cannot honestly say that I have any certainty at all as to my body's supposed set point, if indeed it even has or ever had such a thing. So that particular concept isn't any good to as far as determining a baseline or take-off point for CR. For now I'm using option (1) until/unless I hear otherwise from someone more knowledgeable than my newbie self.

 

For numerology here's my experience: I slowly gained weight from 160 in early adulthood to a peak of 203 lbs at age 35. I was sick and slow. I exercised a whole bunch and found I could push my weight down to 185 lbs and it would go down no further. Even at that weight, I was still sick and slow. Once I discovered CRON at age 43, my weight dropped from 185 to 155 lbs over a period of 6 months and stayed there for about 3 1/2 years. For me 155 is a BMI of 21. At max my BMI was about 24.9. I found that I could achieve this all with a diet of 1750 calories. My current weight is 161 lbs and I'm working my way back down to 155 again after breaking a couple of ribs and gaining some weight during recovery.

 

Keep on with it and maybe we'll see you at the CRSociety meeting this summer in California, if you feel like travelling.

 

Thanks for your personal rundown of the numbers. Personal examples are quite helpful with this stuff. I'd love to attend the CRSoc meeting but I don't seem to be that much of a traveller these days -- too broke to afford it!

[keithsct]

There's a body-weight equilibrium point for every possible weight that a person can create on their body frame. The set point for CR is defined as the equilibrium point at which the subject has minimal excess fat and can maintain that weight without special effort. (I paraphrase)

 

Perhaps the experimental version will be a little more helpful. Suppose you have 100 mice that are all about the same age/species/size. You divide them into two groups of 50. You feed the control group as much as they want to eat. You feed the target group 75% of what the control group eats. Both groups have their diets analyzed to make sure that neither is undergoing malnutrition. So the CR group is said to be on 25% CR.

 

Now it's not being a good citizen if you round up 100 people that are about your same age, height and weight then put them in to a facility and feed them to find out what they eat. Even worse, if you ask them what they eat with questionnaires people sometimes lie or make mistakes. One way to estimate the set point is to take the weight shortly after your teen age years have finished, and before you pile on all the fat. However, these days more and more teens are obese even before they finish their teen years.

 

I like to think of the set point as the lowest amount of calories you can eat and still maintain a stable weight when you exercise quite a bit (not excessively eg. 3 - 4 times a week 1hr per session). Then if you cut that 25%, then you're on 25% CR. For me I was eating about 2300 or 2400 calories before I started CR. I gradually stepped it down 100 calories per month like 2000, 1900, 1850, 1800, 1750, 1700, 1750 .... I found that at 1700 I couldn't think very well at my job, so that was my bottom.

 

Since experiments on people are expensive and subject to many regulations, It's hard to come up with the data to produce a hard and fast rule. Also people can vary enormously, so such a rule would be provided with a very wide error margin anyway.

 

I hope that helps.

[JJeffreyBragg]

Perhaps the experimental version will be a little more helpful. Suppose you have 100 mice that are all about the same age/species/size. You divide them into two groups of 50. You feed the control group as much as they want to eat. You feed the target group 75% of what the control group eats. Both groups have their diets analyzed to make sure that neither is undergoing malnutrition. So the CR group is said to be on 25% CR.

 

The experimental analogy breaks down immediately because it treats the mice as "two groups" without reference to individual food intake although we are trying to establish CR norms for human individuals. There's no knowing which mice are eating more and which are eating less; the possibility exists that some might be thriving whilst others are close to malnutrition. Unless they are individually caged and fed one is reduced to assuming that there is no functional difference between one mouse and another. Even with highly-inbred specialised strains in which differences between individuals are minimal this caution is likely to be applicable. So this tells us nothing about how to establish a baseline for a human individual.

 

Now it's not being a good citizen if you round up 100 people that are about your same age, height and weight then put them in to a facility and feed them to find out what they eat. Even worse, if you ask them what they eat with questionnaires people sometimes lie or make mistakes. One way to estimate the set point is to take the weight shortly after your teen age years have finished, and before you pile on all the fat. However, these days more and more teens are obese even before they finish their teen years.

 

Yep, questionnaire data are likely to be suspect with respect to accuracy and reliability. ;) And yes, the childhood and teenage obesity epidemic is truly a deeply disturbing phenomenon.

 

I like to think of the set point as the lowest amount of calories you can eat and still maintain a stable weight when you exercise quite a bit (not excessively eg. 3 - 4 times a week 1hr per session). Then if you cut that 25%, then you're on 25% CR. For me I was eating about 2300 or 2400 calories before I started CR. I gradually stepped it down 100 calories per month like 2000, 1900, 1850, 1800, 1750, 1700, 1750 .... I found that at 1700 I couldn't think very well at my job, so that was my bottom.

 

What you describe is essentially a process of trial and error, which is exactly what I'm engaged in at this moment. From the 826 kcal/day level that was resulting in fairly rapid weight loss, I've upped my intake to 1250 kcal/day to see whether the weight loss now stops or merely slows down. The trouble is that one's own psychology introduces unwanted variables! My newly-established CR eating habits (I am and have long been primarily a two-meal-a-day person, with perhaps an added late snack in the evening) seem to result naturally in a 1000-1100 kcal/day menu, giving me a left over 150-250 kcal/day for "treats." Now the nature of these treats is apt not to be another serving of salad or vegetables! More likely a cup of hot chocolate and a couple of cookies, or a small whole-grain muffin dressed with peanut butter and blueberry jam. And I cannot help suspecting that the calories that represent those treats might be qualitatively different to those of my main meals, that they may be more likely to result in stored fat. So I wonder: IS there a qualitative difference, or is there none in this regard? A calorie is a calorie is a calorie -- or not? Some people seem to have no trouble snacking on carrot curls and celery stalks, but I'm not really in that category. I can improve the *quality* of my treats, but I like them still to be recognisable as treats. :P

 

Since experiments on people are expensive and subject to many regulations, It's hard to come up with the data to produce a hard and fast rule. Also people can vary enormously, so such a rule would be provided with a very wide error margin anyway.

 

The Delaney/Walford book abundantly confirms those enormous variations! Humankind make abysmally poor experimental subjects in most cases.

[keithsct]

One of the hallmarks of a CRON diet is that you're taking in just enough calories and all of your nutrition. Your body will use up all that energy when you're at a equilibrium point or where you're deficient in calories. So in that way, I'd suggest that there isn't too much difference when it comes to carbs or fat. Your body burns it all anyway. Protein can influence things a bit differently, because the body almost never wants to burn protein for energy. It's a last resort. But lots of protein encourages IGF-1 increase which can induce growth in an adult body when it's not really wanted. More flesh requires more calories. So many of the CRSociety members have been recommending a low protein, low calorie, high nutrition diet lately. We're all pretty healthy, so it must be working for most of us.

 

If you have calories to use on "treats" then you could be relying on supplements too much for your vitamin and mineral intake. You should try to get as much as possible from foods before you rely on supplements. In general, supplements are absorbed poorly compared to foods. We usually limit treats to weekends and special occasions, but I don't want to take all the fun out of life.

[JJeffreyBragg]

One of the hallmarks of a CRON diet is that you're taking in just enough calories and all of your nutrition. Your body will use up all that energy when you're at a equilibrium point or where you're deficient in calories. So in that way, I'd suggest that there isn't too much difference when it comes to carbs or fat. Your body burns it all anyway. Protein can influence things a bit differently, because the body almost never wants to burn protein for energy. It's a last resort. But lots of protein encourages IGF-1 increase which can induce growth in an adult body when it's not really wanted. More flesh requires more calories. So many of the CRSociety members have been recommending a low protein, low calorie, high nutrition diet lately. We're all pretty healthy, so it must be working for most of us.

 

If you have calories to use on "treats" then you could be relying on supplements too much for your vitamin and mineral intake. You should try to get as much as possible from foods before you rely on supplements. In general, supplements are absorbed poorly compared to foods. We usually limit treats to weekends and special occasions, but I don't want to take all the fun out of life.

 

Now THAT'S a pithy summary if ever I read one! Thanks for that, Keith, you clarified a couple of issues there quite economically and effectively. My understanding is increasing by leaps and bounds.

 

Today the Roy Walford book (Beyond the 120 Year Diet) finally arrived in the post! I am very impressed by this book. Dr. Walford wrote so clearly and effectively. I've been dipping into it over the past few hours, superficially as yet but at this point can certainly say that it appears to be a very elegant, comprehensive and compelling presentation of his own concept of CRON. I look forward to reading every word of it. It's tragic that amyotrophic lateral sclerosis claimed his life prematurely. He gave us all so much, yet one cannot help but feel that he had much more still to give had he survived for a couple more decades. The void he left obviously has yet to be filled.