I was a practitioner of Caloric Restriction with Adequate Nutrition (CRAN) in the 1990s, as I described in my 1995 CRAN documentation and my 1998 CRAN documentation. After well over a decade of not practicing CRAN other than to avoid unnecessary eating, I returned to the practice in 2010 — although my goals and my methods have been different from what they once were.
In the 1990s I had been attempting to have a fat-free diet, which led to heart problems that caused me to abandon calorie restriction in a panic. A diet without essential fatty acids is not "Adequate Nutrition". Despite my subsequent studies on essential fatty acids and DocasaHexaenoic Acid (DHA), I did little more than mildly restrict my diet. I was determined that if I ever resumed the practice of CRAN that it would be without counting calories and weighing food.
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My weight in the first decade of the 21st century was in the 140+ pounds range (I am 5'7" tall). My diet was very healthy for the most part — mostly ovo-lacto-vegetarian except for occasional meat — although I now believe that I was addicted to fruit. Fruit sugar is mostly fructose, and fructose promotes insulin resistance & weight gain — to say nothing of overeating [AMERICAN JOURNAL OF CLINICAL NUTRITION; Elliot,SS; 76(5):911-922 (2002)]. I had too much of a sweet tooth. Snacking is really deadly. I find it much, much easier to go for long periods without eating than to try to eat in small quantities. A little bit of food creates a strong temptation to have more (and is thus not very satisfying).
In the summer of 2010 I took a ten-day trip to England, where it was hard for me to find the "healthy food" I had been consuming on a regular basis at home. When I returned I discovered that I had lost over five pounds. Somehow this inspired me to get myself down to 130 pounds and hold my weight there.
Aside from all the fruit snacking I had been doing during the day prior to my trip, I had been eating basically two meals per day accompanied by supplements. My sense that it is important to get all my supplements — and that supplements should be taken with food — has been a rationalization for much unnecessary eating ("eating by the clock").
My dinner meal had grown particularly large. It consisted of about 2 cups of broccoli crowns blended with whey protein & linseed in water in an industrial-strength blender. Plus half an avacado. I felt this was not enough solid food, so I also had half a cup of microwaved egg-white mixed with oatmeal, cheese and walnuts. Upon my return from England I decided to split my dinner meal and have the blended broccoli and egg-white mix on alternate days. I would still have half an avacado daily. The avacado is to help with absorption of the oil-soluble nutritional supplements. I cut-out most of the fruit I had been eating, except blueberries and occasional strawberries. I had adopted the practice of chewing Trident gum — partly for the low-calorie sweetness, and partly for the tooth-clensing benefit. I was able to drop below 130 pounds.
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My mid-day meal consists of plain non-fat yogurt to which I add blueberries, oatmeal, and walnuts. I had been eating cashews regularly until I decided that cashews go rancid too easily, and caused me to be consuming advanced-glycation end-products. I am somewhat committed to eating blueberries regularly because of the reputed benefits for aging & cognitive function — with help from strawberries & walnuts [THE JOURNAL OF NUTRITION; Joseph,JJ; 139(9):1813S-1817S (2009)].
Prior to Spring 2010 I only exercised three times weekly. But in the Spring I had visited a cardiologist because of ST segment depression I had gotten on treadmill electrocardiogram tests. My heart proved to be in great shape, but I decided to begin exercising daily — partly for the cardio benefits and partly to relieve some of the great emotional stress I am often subject to. I spend 45 minutes per day on my own stairmaster. Exercise and dietary protein are both of great value for the weight loss phases of CRAN.
To help prevent hemorrhoids associated with CRAN, as well as to reduce the risk of colon cancer associated with inadequate fiber and bulk, I resumed my practice of eating a high-fiber "snack". The quotes are relevant, because it is not very tasty. The "snack" consists of containers of:
125 ml (1/2 cup) Fibre One Cereal
125 ml (1/2 cup) Quaker Oat Bran
125 ml (1/2 cup) Wheat Bran
When I eat one of these containers, I first mix 15 ml (a tablespoon) of unflavored, sugarfree Konsyl (formerly I was using Metamucil) (100%w/w psyllium hydrophilic mucilloid) with water in a bowl until I get a thick, uniform liquid. Then I dump-in the container contents and mix to get an incredibly high-fiber "meal". I eat these containers once every few days, and well-apart from my regular meals because I believe they would interfere with the absorption of my supplements (especially the minerals). Oat Bran lowers blood cholesterol, and blood glucose and blood insulin — the latter of benefit in reducing glycation (see my article Mechanisms of Aging). Wheat Bran and psyllium both reduce the chance of hemorrhoids and in animal experiments are highly protective against colon cancer [CANCER LETTERS; Alabaster,O; 75(1):53-58 (1993)]. FIBRE ONE has wheat bran & corn bran and is sweetened with aspartame rather than with loads of sugar (unlike the other high fiber cereals).
I became increasingly concerned about a bad taste that I had in my mouth after chewing Trident gum for long periods. Chewing gum had the best mouth-clensing and anti-tooth decay action if chewed for more than twenty minutes after eating. Trident ingredients include artificial flavoring, which I thought might be a problem. Also, the main sweetener is sorbitol, rather than xylitol. Xylitol in chewing gum is much more effective than sorbitol for reducing tooth decay. Searching the internet for chewing gums with natural ingredients and xylitol sweetener, I found Spry and Xylichew. Spry contains only 1.7 calories per piece, and it is much less expensive, but it also tastes terrible after lengthy chewing. Xylichew has 1.9 calories per piece. These calories mostly seem negligible, except that I like to chew with 8-10 pieces in my mouth at a time to give me a good sense of substantial chewing.
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After a couple of months I decided to target 125 pounds, and hold that weight. I was able to achieve this without great difficulty simply by skipping my midday meals for a few days, and eating nothing all day except my (reduced) dinner. I simply dropped my quasi-religious ritualistic attachments to getting my supplements on schedule (figuring the weight loss would have compensating health benefit).
I stabilized at 125 pounds for a couple of months, but my ultimate objective was to stabilize at 120 pounds. I did not want to loose too much weight all at once, however, because I think too much weight loss too quickly is harmful.
Getting from 125 pounds to 120 pounds was much harder than getting from 130 pounds to 125 pounds. I had to go 48 hours without eating to get to 122 and another 72 hours to get from 122 to 118.4. I believe that I have been on 3-day water fasts before without so much discomfort. I do not want to be spending all day in a miserable condition wanting for food on a regular basis. I justified the effort on the grounds of weight loss. I find, however, that napping can do wonders for eradicating hunger discomfort.
I achieved 120 pounds toward the end of November 2010, and found that it was not too difficult to maintain 120 once I achieved it. I prefer to stay slightly below 120 to assure myself that I am not drifting upward. Two modest meals per day, plus occasional skipping of the midday meal is all that is required — plus 45 minutes per day of stairmaster followed by 12 pushups.
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I believe that 120 pounds is about as far as I am willing to drop my weight and practice CRAN. I think everyone has a limit to how much pleasure they will sacrifice or pain they will endure to extend lifespan. And it is reasonable to discount the value of future life against current life (although being alive in the future is qualitatively different from enjoying life in the present). For now, the stress and attention required to maintain 120 pounds is enough of a challenge and distraction.
It is hard to say what my "setpoint" is, but I'd estimate about 140 to 145 pounds. I have been as high as 160 pounds in the past. At 140 I felt that I was at least modestly restraining my calorie intake. But using 140 as the setpoint. 120 pounds represents about a 15% calorie restriction.
That level of CRAN is significant for comparison with a study of mice that were 10% to 15% calorie restricted. The mice showed increased sensitivity to stress, as indicated by higher amounts of corticosterone released in response to mild stress stimulus, such as loud noise. The dieting mice took longer to calm down after being stressed. The mice were vulnerable to binge eating of high-fat foods [JOURNAL OF NEUROSCIENCE; Pankevich,DE; 30(48):16399-16407(2010)].
I find that discipline about eating times and eating amounts is the best defense against binge eating. When there are no eating rules, impulses favor more eating. Moreover, eating is an appetizer — which is why infrequent eating of regular meals is better than frequent nibbling. I can experience a great deal of stress in my work as President of the Cryonics Institute, so added stress from CRAN might seem ill-advised. To deal with this stress I have not only adopted 45 minutes of daily stairmaster exercise, but I have begun periodically engaging in meditation.
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There is skepticism that lifespan extension with CRAN in short-lived species can be generalized to long-lived species. Even if CRAN could not extend maximum lifespan in humans, I think that it likely increases average lifespan. A comparison of a 20% extra calorie utilization by exercise with a 20% reduction in calories by CRAN in human subjects for over one year showed comparable reduction in oxidative DNA damage (nearly 50%) in white blood cells [REJUVENATION RESEARCH; Hofer,T; 11(4):793-799 (2008)]. Human subjects who experimentally made a 6% weight gain (80%s of which was fat) showed a decline in endothelial function of about 15% [JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY; Romero-Corral,A; 56(8):662-666 (2010)]. Eight normal human subjects (4 male, 4 female) in Biosphere on 1780 calories/day had an 11% (female) to 16% (male) average drop in BMI over six months. Systolic blood pressure dropped an average of 18% and diastolic blood pressure dropped an average of 21% . There was a 20% drop in fasting blood glucose and a 30% drop in leucocyte count [PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES (USA); Walford,RL; 89(23):11533-11537 (1992)].
I think that it is highly probable that a decline in risk factors and a decline in tissue damage — seen in association with human practice of CRAN — results in an increase in lifespan. Even if maximum lifespan does not increase, average lifespan should certainly increase.
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