Impact of caloric restriction on health and survival in rhesus monkeys from the NIA study.


rhesus monkeys truth rosedale comments1 Impact of caloric restriction on health and survival in rhesus monkeys from the NIA study.  We have received a lot of questions regarding this study pertaining to calorie restriction in rhesus monkeys.   Here are a few quick, off-the-cuff thoughts that I will expand on at a later date.

It should be noted that there was a small reduction in mortality (24% in the control group versus 20% in the CR group in young onset CR initiation). Their results contrasted sharply with life prolonging affects seen in rhesus monkeys at the Wisconsin National Primate Research Center trial, where 37% of monkeys in the control group died compared to 13% in the CR (caloric restriction) group at the time of publication a few years ago..

Click on the link below to see the study.

Impact of caloric restriction on health and survival in rhesus monkeys from the NIA study

One factor that is mentioned in this NIA study to try to explain why their results contrasted quite significantly from the primate study done at the Wisconsin Primate Research Center is that “diet composition may strongly affect the life prolonging effect of calorie restriction in a long-lived nonhuman primate”. I would have to see exactly what they were feeding the monkeys at each of the centers to ascertain a difference, however, I do know that they were feeding the monkeys approximately a 60% carbohydrate diet at NIA. That may be way too much to ascertain a clear benefit of CR (caloric restriction) to life extension. Additionally, triglycerides increased throughout life in both the control and calorie restricted groups. This indicates that burning energy from fat was quite limited in both groups.  I believe that what I have said for two decades is very true; that health and longevity will be determined by the proportion of fat verses sugar one burns over a life time.  The monkeys in this study were likely still being forced to burn sugar and minimal fat as their primary fuel, secondary to the high carbohydrate diet they were still being fed.

I have long maintained that it is not calorie restriction but carbohydrate and protein restriction that mediates effects of longevity, and that typical calorie restriction reduces calories from both proteins and carbohydrates to a very limited extent. I feel one can go much further in showing benefits of CR (caloric restriction) with a very low carbohydrate, high-fat, and low to moderate protein diet.

It is now becoming known that the health and life prolonging effects of calorie restriction are not due primarily to calorie restriction per se but are mediated through lowering of metabolic pathway signaling, namely insulin, mTOR, and likely leptin in “higher” animals that use fat as a primary fuel. Therefore the macronutrient content of the diet is extremely important, however this was not well known to the experimenters when these rhesus monkey experiments were initiated over two decades ago.

Check out my comments on the new Harvard Study published late in June, 2012, where the Journal of the American Medical Association raised a challenge by publishing a Harvard study involving three different diets, and how each diet affects the likelihood of gaining weight.


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  1. Posted August 31, 2012 at 12:09 pm | Permalink

    Its certainly not hard to agree with your logic.

    Seems a lot of benefits that apply to periods of fasting apply equally to being in ketosis. For example, the benefits of fasted sprinting or HIIT on insulin sensitivity seems about the same if you are fasting, or fed but ketogenic. However adding carbs kills that benefit from what I have seen in various places.

    From my own personal experience the body just seems to work differently when you become lipid powered. My friend once described it as waking from the nutritonal Matrix. He was very right.

    Keep spreading the word Doc!

    • Joshua Session
      Posted August 31, 2012 at 9:25 pm | Permalink

      Yes insulin sensitivity improves the most when you exercise on a low carbohydrate diet. I read the study and it isn’t calorie restriction but carbohydrate restriction that does it. Another study I found on centenarians made the observation that people who live to one hundred have “preserved” insulin sensitivity.

  2. Ron
    Posted August 31, 2012 at 7:14 pm | Permalink

    Calorie restriction was attempted in monkeys largely based upon its decades-long proven track-record of effectiveness in rodents and other “lower” organisms. There is *no* substantial evidence, even in rodents, that the diet you are suggesting of “carbohydrate and protein restriction”(ie high fat) increases lifespan. What you are suggesting is speculation, and speculation that contradicts rodent experiments.

    On a related note, high fat diets are used specifically for their known ability to cause obesity in rodents, in fact.

    • Dr. Ron Rosedale
      Posted August 31, 2012 at 11:13 pm | Permalink

      This is not just speculation by me. It is simple deduction. If raising insulin and raising mTOR reduces lifespan, and lowering insulin and lowering mTOR increases lifespan, then what would be your idea of a health and lifespan enhancing diet? I for one would not want to wait a half a century or more for a human trial, nor do I think that is necessary. If you want to call my thoughts speculation, that’s fine with me also. All advances in science are made by educated “speculations”.
      Albert Einstein, “I believe in intuition and inspiration…At times I feel certain I am right while not knowing the reason…Imagination is more important than knowledge. For knowledge is limited, whereas imagination embraces the entire world, stimulating progress, giving birth to evolution. It is, strictly speaking, a real factor in scientific research.”

      As far as “high-fat diets” being used to fatten mice; you must read the studies first. Almost all of the so-called “high-fat” diets used in research are actually even higher in carbohydrates; they are just somewhat higher in fat than the typical very low fat, very high carbohydrate diets used in typical rodent chow. The worst diet to be on is one that is both high in carbohydrates and fat, the sugar formed preventing the fat from being burned. I have used my diet essentially unchanged for 2 decades with much success to treat severe chronic diseases of aging including in overweight and obese people where extra body fat is nearly always lost/burned as a side effect. This effect on weight/fat loss has been documented in subsequent similar diets to mine in numerous scientific papers.

      • Ron
        Posted September 1, 2012 at 8:16 pm | Permalink

        Current nutritional and biological science are light-years away from a complete understanding of rodents or humans. As shown by the this study, even some of the most experienced scientists who have had years of successfully extending lifespan in rodents using calorie restriction have been unable to translate this to primates.

        When attempting to make predictions brought about by alterations to immensely complex and poorly understood systems(ie predicting increased lifespan of rodents/humans by alteration to metabolism), the use of “simple deduction” is inescapably going to be speculation.

        Focusing on just a single or a couple of variables (e.g. the currently “trendy” mTOR or insulin) of the likely millions or billions or trillions(literally!) of potentially relevant variables that are impacted by calorie restriction or carbohydrate/protein restriction is again absolutely going to be speculation.

        Where are the high fat, low protein, low carbohydrate life-extended rodents? Proposing an intervention(carbohydrate/protein restriction to increase lifespan) that does not even have substantial evidence in rodents, let alone primates, let alone humans, is absolutely speculation.

        Speculation is certainly an important part of scientific advancement. But for such advancement to take place it is also very important to understand when, and be abundantly clear when, one is indeed speculating.

        As for the commonly-used obesity-inducing high-fat rodent diets, my impression(which could be wrong) was that the diets were often much higher in fat than in carbohydrate content. For instance:

        “This study characterizes the high-fat diet-fed mouse as a model for impaired glucose tolerance (IGT) and type 2 diabetes. Female C57BL/6J mice were fed a high-fat diet (58% energy by fat) or a normal diet (11% fat). Body weight was higher in mice fed the high-fat diet already after the first week, due to higher dietary intake in combination with lower metabolic efficiency. Circulating glucose increased after 1 week on high-fat diet and remained elevated at a level of approximately 1 mmol/l throughout the 12-month study period. In contrast, circulating insulin increased progressively by time……

        …..On caloric basis, the high-fat diet consisted of 58% fat from lard, 25.6% carbohydrate, and 16.4% protein (total 23.4 kJ/g), whereas the normal diet contained 11.4% fat, 62.8% carbohydrate, and 25.8% protein (total 12.6 kJ/g).”[1]

        Do you think that almost 60% calories from fat, and just 25% calories from carbohydrates, could be characterized by your description as “both high in carbohydrates and fat”? I certainly don’t.

        Given your interest in insulin, it’s also interesting to note the gradual ongoing increase in insulin seen in the high fat diet mice group.


        1: Winzell MS, Ahrén B. The high-fat diet-fed mouse: a model for studying
        mechanisms and treatment of impaired glucose tolerance and type 2 diabetes.
        Diabetes. 2004 Dec;53 Suppl 3:S215-9. PubMed PMID: 15561913.

        • Dr. Ron Rosedale
          Posted September 6, 2012 at 6:27 pm | Permalink

          The worst diet to be on is one that is both high in carbohydrates and fat, the sugar formed preventing the fat from being burned…And the diet you mention is still too high in carbs to burn fat effectively. If one is going to go on a high fat diet, the (non-fiber) carb intake has to be very low. 100 gm/day carbs in humans is enough to totally prevent ketosis. This is a major reason that I believe there is no such thing as “safe starches”.

          As far as speculation again; there are perhaps 100s of studies now that show a connection between insulin and mTOR and the biology of aging, many being very robust genetic intervention studies. Mimicking down regulation of those same genetic pathways using dietary control is not just speculation, but quite sensical..

  3. Posted September 3, 2012 at 12:46 pm | Permalink

    I find high fat, coupled with high protein, nutritionally dense foods and ‘real foods’ with the vegetable portions being as near to raw as possible and done with ‘intermittent fasting’ and exercising while fasting before eating high fat=high protein is clearly the healthiest.

    I think the logic for this is it would be the way we lived for more than 200,000 years as humans and for millions of years as we evolved through our line of hominids.

    When we hunt for food we do two things, we gather and eat fresh raw vegetative matter and some fruits when in season. In northern climates I am sure we learned how to dry and store those materials.

    During animal hunts the hunters consume the heart and liver of freshly killed animals which are the very nutritionally dense organs. Paleolithic research shows they rendered and stored fat and dried meats for winter use.

    The intermittent fasting would be logical because during paleolithic times there were a lack of ‘supermarkets’ and hamster powered refrigerators were unreliable.

    Insulin is a hormone designed to store extra energy (in the form of elevated blood sugar) consumed during the abundant summer months into fat for use in winter.

    But the fasting and exercise would be a natural process. We would wake hungry and go hunt while hungry. We would be ‘fasting’ and chasing down the animals we were hunting ‘exercising’ while fasting. and once we killed we would eat.

    Research being done on intermittent fasting seems to point to two best scenarios.

    Men fast every 3 days and women every 6. Interestingly the Jewish religion has fasting as a weekly ritual of 6 days eating and 1 day fasting. Children and pregnant or lactating women excluded.

    I found when I started on paleo that after about 6 or 8 months, I would just forget to eat for a day because I was not hungry. The longer I have continued the more it seems my need to eat everyday has been reduced. Yet, even though not eating I have a great deal of both physical and mental energy.

    I recommend each of you try this and ease yourself into it, i.e. start by waking up and not eating until you have felt really hungry for a few hours. When you eat, do your best to eat with others and talk while you eat (you’ll find you eat less because hunger seems to have a periodicity of 15 minutes, so if you eat slowly over 15 minutes you will feel satisfied ) I also find eating until you are only 80% full 90% of the time to be better as well.

    Hope all of you find this useful

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