Calories That Count

Michael Lam, MD, MPH
www.DrLam.com

Introduction

Only a single dietary regimen has ever been conclusively demonstrated to extend life span and improve the heath of laboratory animals and humans. It is known as calorie restriction (CR). Together with exercise, this is as close to the magic bullet as one can hope for in anti-aging. There are very few, if any, disagreements among anti-aging experts that calorie restriction can increase longevity.

The average human consumes 1,500 calories a day. The average American consumes 2,100 calories a day. For most of the population, calorie restriction means taking in about 20-30 percent fewer calories. For those serious about CR, the restriction can go up to 40%. In other words, the average-size human on a CR diet might consume 1,500 calories a day, compared to the 2,100 calories of the typical American. This anti-aging diet is made up of four or five small meals a day and consists predominantly of vegetables and fruits. "It requires a psychological profile only one person in 1,000 has," says Richard Miller, associate director for research at the University of Michigan Geriatrics Center.

Nevertheless, CR diets are widely practiced by anti-aging experts. The reasons are clear - the list of the beneficial effects of CR reads like the packaging on a miracle cure. Benefits include: Increased average and maximum life spans and reduction in occurrence of virtually all age-related diseases, including heart disease, diabetes, autoimmune disease, ocular degeneration, blood pressure, and cancer.These reductions range from two-fold to as much as ten-fold. (For example, 50 percent of female control mice of a particular genetic strain develop breast cancer, but only 5 percent of the same strain developed cancer if on a CR diet.) 

Two caveats - the diets must include plentiful amounts of vitamins and minerals, and the subjects must be undernourished without being malnourished.



Calorie Restriction vs. Malnutrition

Calorie restriction is different from malnutrition, starving or extended fasting. These practices actually accelerate the aging process as they create nutritional deficiencies. Calorie restriction, if properly carried out, provides the body with all the nutrients it needs without overburdening the organs and system functions. By limiting calorie intake to the level required by the body for optimum functioning (as measured by the maintenance of lean body mass), that miraculous machine, your body, will self-regulate. When you eat more food than you need, the engine of your body goes into overdrive in order to digest the food and store what you don't need in the form of fat. If you restrict your food intake to only what you need to maintain a physical and active lifestyle, your body automatically tones down its basal metabolic rate to conserve the limited amount of energy it receives. This is your body's mechanism for survival.

Like an old car, your body's engine needs premium gasoline to prime itself as you age. If you are not mindful of this and continue to abuse your body with "non-premium" gasoline and rough outings (like going on an eating binge), you are causing unnecessary strain to your body's organs. Sooner, rather than later, your body will break down.

What happens to your body as your calorie intake decreases? First, the work necessary to digest food decreases. In other words, there is less oxidative stress. Second, the body's metabolic rate automatically slows and readjusts itself to match your energy expenditure to that of the intake. This is the body's way of preserving itself. Third, the slowing down of your organ system gives your organs more rest and prolongs the life span of each of the organs. As your organs remain healthy, you live longer.

Malnutrition and starvation are extreme forms of calorie restriction, which is age accelerating and should be avoided. A car cannot run without gasoline, and your body needs food to generate energy. During malnutrition or starvation, your body breaks down your muscles and organ structures for energy, which is very destructive.


Mechanism of Action

The question of how CR works is still open to debate. The leading hypothesis is that calorie restriction reduces the amount of oxidative damage to the body. Oxidative damage is the foremost theory as to what causes the deterioration that comes with age. This concept is known in anti-aging as the "oxygen paradox." While oxygen is required for life and cellular fuel, the side effects of oxygen metabolism are detrimental to our heath. The process takes place in cellular factories called mitochondria, where energy for our body is produced and by-products called free radicals are also produced. These free radicals are short-lived but voracious agents that oxidize and damage tissues. The oxidation that occurs in the human body is identical to the way in which rust is formed on metal, so it is not unreasonable to say that we will all eventually "rust to death" if given the opportunity. The free radicals not only damage the tissue, but also seem to damage the DNA, genetic material that codes for proteins required for the body's physiological functions.

CR reduces the amount of fuel available for cells and the amount of oxygen needed by the mitochondria to convert the existing fuel into energy, and it makes the existing metabolic process more efficient. With CR, fewer free radicals are generated, the production of enzymes that neutralize the free radicals increases, and growth hormone levels increase.

CR's effect of lowering oxidative damage is targeted at critical cells in organs, such as the brain, heart, nerves, and skeletal muscle cells. All these tissues depend heavily on mitochondrial energy metabolism to generate cellular energy, and all these tissues have fairly limited self-repair ability.

In addition to lowering oxidative damage, CR has been proven to increase endogenous growth hormone release from the pituitary gland. Raising the growth hormone level is key in deterring the aging process, as symptoms of aging follows the decline in growth hormones in our bodies.

CR also stimulates the release of our body's internal antioxidants, such as super oxide dismutase (S.O.D.). Research has shown that administration of S.O.D. leads to a reduction of free radicals and an increase in life span.

A properly carried out CR program will limit the amount of sugar intake by up to 90 percent. Sugar is a negative fountain of youth. It accelerates aging and increases the body's cortisol level. Cortisol is a hormone, but unlike other hormones, it increases with aging. It is sometimes called the "bad" hormone because its increase is linked to accelerated aging.

In summary, calorie restriction:

• Increases the ability of the body to repair damaged DNA.
• Decreases oxidative (free radical) damage in the body.
• Increases the levels of certain protective/repair proteins that respond to stress.
• Improves glucose-insulin metabolism by lowering glucose levels in the blood.
• Increases the release of growth hormone from the pituitary gland.
• Increases the production of endogenous antioxidants such as S.O.D.