I have pointed out in other articles the striking contrast between, on the one hand, the feverish interest shown calorie restriction by scientific researchers and, on the other, the virtual invisibility of CR amid a population otherwise obsessed with dieting. As I have elsewhere opined, I think the latter is largely due to a failure on the part of those who do know (but whose expectations are cynically low) to inform and educate those that don’t.    

Meanwhile, expectations are very high among those studying the nature and effects of calorie restriction. Since 1935, when Clive M. McKay at Cornell University first stumbled across the CR phenomenon, over 1000 CR-related studies have been conducted at major universities around the world. These studies generated over 100 articles in prominent medical and other scientific journals, including JAMA, Lancet and New England Journal of Medicine. This vast and prolonged scientific gold rush was triggered by a very concrete discovery: When an organism, for example an animal, consumes substantially fewer calories (20-40%) than it normally would, its lifespan is extended beyond the maximum lifespan for its species.

This was an earth-shattering discovery. To fully appreciate this assertion you need to understand the difference between average life span and maximum life span. When health experts speak of ways to lengthen your life, to add years to your life, they are referring to ways that you can increase your average lifespan. In other words, no one can accurately tell you that a given behavior or product will extend your life in particular. The fact is that you in particular may die tomorrow in a plane crash or next year from a rare genetically-determined cancer. What experts can tell us is that certain things will increase the average health and longevity among members of a given population. There are a lot of these things: stop smoking, exercise regularly, eat lots of fruits and vegetables, use a seat belt. Studies show conclusively that when applied among a large representative sampling, the average life expectancy is higher. 

While this is interesting and very valuable information, it pales in significance when compared to the things that allow an organism’s lifespan to plunge through the ceiling of its species, i.e. to surpass the specie’s maximum life span. For example, look at the most popular conventional strategy for increasing average lifespan: aerobic exercise. Beginning in the early 1970s,  Dr. Kenneth Cooper and other influential proponents have persuaded many if not most educated Americans to either exercise regularly or feel guilty that they don’t. While the health benefits of aerobics can be measured in more than one way, the longevity effect is probably the most telling. Furthermore, since the runners have been running now for almost 40 years, the jury is in regarding the impact of aerobics on average lifespan.

Though there is room for disagreement regarding the details, the bottom line is that we are talking about single digit gains. This has been the nature of health discoveries after the middle of the last century. In the hundred or so years before there were quantum gains attributable largely to advances in environmental safety and infectious disease control (e.g. vaccinations, antibiotics, sterilization). But these were low hanging fruit that related less to our body’s intrinsic capabilities than to external threats. Going forward, as our present average exercised life span of 80 years encroaches on the human maximum life span of 115 years, gains are likely to become more effortful and incremental before finally butting against the brick wall.

Consequently, the real action, scientifically and commercially speaking, relates to the metabolic changes triggered by calorie restriction but without the restriction of calories. The truly good news is that such a metabolic phenomenon even exists. Except for calorie restriction, there would be widespread skepticism among scientists that its even possible to extend the life of an organism beyond its maximum life span. Such things were discussed more in science fiction than science. Now that we are past that hurdle, the frenetic race is on. Meanwhile, as the research proceeds, discoveries are occurring along the way that require medical professionals to think differently about the diagnosis and treatment of disease. Following are a couple of interesting examples:

  1. Traditionally, physicians have considered a patient’s white blood cell count (also called “leukocytes”) a very important indicator of his immune health, of his ability to fight off various diseases and infections. Standard lab tests measuring white blood cell counts consider a count below 4,500 white blood cells per microliter (mcL). an unfavorable marker which indicates the immune system is impaired, that the patient has a greater vulnerability to disease. Yet calorie restriction studies show that CR subjects consistently have  white cell counts substantially below the reference range while demonstrating exceptionally effective immune function. In the human study presently being conducted at Washington University in St. Louis, in which I am a participant, virtually all the CR subjects show medically low white cell counts yet are much healthier than their non-CR counterparts. They also report fewer colds and other illnesses as well as fewer allergies now than before CR. (Further investigation suggests that the answer likely lies in a sub-group of cells. CR practitioners, while low regarding all white cells, are actually very high respecting this particular subgroup. If this theory is confirmed it will explain the CR white cell paradox as well as inform the  medical profession of a long-standing diagnostic error.
  2. Bone health has traditionally been determined by measuring a person’s “bone mineral density”(BMD). The is done with a special x-ray device which measures the mass of the bone. If someone’s BMD is more than one standard deviation less than that of a healthy young adult, he is said to have osteopenia, generally considered a call to action if one is to head of the dreaded diagnosis of osteoporosis,  defined as more than 2.5 standard deviations from the reference BMD. A low BMD is considered an indicator of weak bones and an accompanying higher risk of fracture. Calorie restriction research, however, suggests that BMD is not a reliable test of bone health. The human CR study at Wash U has studied closely the bone health of the CR participants and has found them to have functionally strong bones despite low BMDs. None of the participants have reported any fractures or other such problems despite substantial levels of activity. As with low white cell counts, practitioners of CR consistently have lower BMDs than their more caloried counterparts. Researchers believe that the bone loss that a person experiences when he adopts CR is akin to the myriad other adaptations that the body makes as it becomes increasingly efficient and healthy. 

    Bones are dynamic organs and it turns out that their mass expands and contracts with changes in the body’s structural and other needs. If someone is carrying 300 pounds of body weight, for example, he will require larger bones than the same person carrying 150. The body is smart enough to sense such changes and to make appropriate adjustments. What is most interesting, however, is that bone strength, integrity, does not appear to have been compromised through such adaptations despite the loss of density. Clearly this suggests that the gold standard for measuring bone health, BMD, needs to be replaced, along with the indiscriminate standards regarding treatment of osteopenia .