The Long-Life Diet: Nutrition for Longevity, Chapter Thirteen

No matter the amount of research that scientists do into anti-aging medicine, no matter how skilled physicians become in using these tools, if people will not turn their own attention to changing their diets for the better, there can be no completely successful cases in the realm of longevity medicine. It's just that important.

Proper nutrition must be combined with appropriate exercise and necessary anti-aging medicine tools in order to create a fully lived, long, and healthy life.

Diet: The Latest Research

The biggest health problem facing Americans today is obesity. More than half of us are over our ideal weight and more than one-third are obese enough to significantly raise the risk of disease and premature death.

Nutrition is one of the greatest weapons against disease. Keeping fats below 30 percent of total calories consumed and cholesterol intake below 200 mg will markedly cut your risk of heart disease. Eating five servings a day of fruits and vegetables lowers your chances of getting cancer. And a recent study found that eating nine to ten daily servings of fruits and vegetables along with three servings of low-fat dairy products is as effective as medication in lowering high blood pressure, and can help reduce or eliminate your chances of stroke.

It is established that the risk of several other prominent age-related disorders, including cardiovascular disease, cancer, and diabetes, is influenced by the nutrient value of the food you eat and by the level of food intake - high food intake increases risk, and low food intake reduces risk.

A number of studies indicate that moderate calorie restriction can extend the life span. Dr Sonntag and colleagues from Wake Forest University School of Medicine in South Carolina conducted a study of lab animals in which they restricted the caloric intake to 60 percent of normal.

The team found that moderate caloric restriction induced a wide range of physiological changes. Of particular importance were adaptive changes within the endocrine system that serve to maintain blood levels of glucose (sugar). Specifically, Dr. Sonntag's team observed that growth hormone secretion increased and plasma levels of IGF-1 decreased. Noting that these adaptive mechanisms to maintain glucose can be induced at any age, the team suggests that these alterations reflect some of the many beneficial aspects of moderate caloric restriction.

Further, Dr. Sonntag notes that numerous studies indicate that growth hormone and IGF-1 decrease with age and that administration of these hormones ameliorates the deterioration of tissue function evident in animals left to eat as they desired. Dr. Sonntag proposes that endocrine compensatory mechanisms induced by moderate caloric restriction decrease the stimulus for cellular replication, resulting in a decline in pathologies and increased life span.

Additionally, dietary restriction may stave off the onset of the neurodegenerative process. Dr. Mattson from the National Institutes of Aging published findings in 2000 indicating that diseases including Alzheimer's disease are precipitated by increased levels of oxidative stress, perturbed energy metabolism, and accumulation of insoluble proteins. Dr. Mattson suggests that dietary restriction may enhance the resistance of neurons in the brain to metabolic, excitotoxic, and oxidative insults that are associated with Alzheimer's disease and other neurodegenerative disorders.

As we age, the nutritional value of dietary intake becomes very important. It has been suggested that the age-associated declines in immune function are similar to that seen by protein-calorie malnutrition. Additionally, many older people live alone and may not give adequate attention to the quality of foods they consume. Many older men and women are deficient in vitamin C, vitamin E, riboflavin, pyridoxine, iron, and zinc.

Several researchers have indicated that proper nutrition can modulate the age-related decline of the immune system. Indeed, Dr. Lesourd and colleagues from the Hopital Charles Foix in France have documented a decline in cell-mediated immunity that is largely responsible for increased rates of infection and cancer in the elderly. Dr. Lesourd's study reinforces the notion that nutritional factors play a major role in the immune responses of older people - and that even the healthy older population can benefit from proper choices in daily nutrition.

The Frustrations of Dieting

Most people who look to dieting as a means of losing weight consider the whole process a rather Sisyphean experience. Just like old Sisyphus, who was cursed by the ancient gods to roll a rock to the top of a hill only to have it roll back down again, dieters often find that their goal weight rushes away from them. Just when they seem about to lose those last few pounds or maintain their new desired weight, they fall off their diets, begin to gain, and the whole dieting cycle starts all over again. A 1993 issue of Consumer Reports put the rate at which this rollercoaster rebounding occurs for dieters at 75 percent. Dr Xavier Pi-Sunyer of St. Luke's Hospital in New York puts the figure even higher, at about 85 percent.

Nutritionists, scientists, and dieters themselves have long quarreled over why weight should be so hard to lose and so easy to gain, especially after one has already established a certain higher-than-optimal weight. The most persuasive theory speaks about the set point, the body's predetermined comfort zone for weight, which represents a complex negotiation of genetic factors, the amount of food available in infancy, and eating patterns as a child and adult. Once the body decides on a set point, however, it mobilizes all of its resources to maintain weight at that level. If weight drops below the set point, the body, fearing starvation, lowers metabolism to burn fat more slowly while at the same time increasing appetite. As weight approaches the set point, metabolism picks up again and appetite decreases.

According to this theory, frequent dieting followed by regular regaining of lost weight confuses the body and causes it to stick ever more stubbornly to its set point. The less food the frequent dieter eats, the lower his or her metabolism drops, so that losing weight becomes extremely difficult and gaining weight seems to take place with virtually any intake of food.

In addition to the frustrations of so-called yo-yo dieting, health professionals have recently raised concerns that frequent weight gains and losses might actually be dangerous to the dieter's health. These fears, however, seem to be largely unfounded. According to a recent survey by the National Institutes of Health task force of forty-three different studies of dieting, "Obese individuals should not allow concerns about hazards of weight cycling to deter them from efforts to control their body weight."

Even if you're not worried about the potential dangers of dieting, what about the more basic problem of finding an effective way to reduce body fat? The bad news is that there is no easy answer. The good news is that with the proper combination of exercise and dietary change, you can alter both your body weight and your chances for a long and healthy life. The dietary changes we'll explore in this chapter aren't so much "diets" as long-term approaches to eating. And the stakes aren't just a slender figure or a chance to wear last year's jeans, but rather a new lease on life.

The Hazards of Fat

Over the past two decades, our society has become increasingly preoccupied with both health and thinness. The popularity of gyms, health clubs, and personal trainers, along with the extremely svelte silhouettes of beauty queens and fashion models, attests to the ideals of fitness and slenderness.

At the same time, more Americans are obese than ever before. According to the American Obesity Association, 61 percent of the U.S. adult population are overweight, and 26 percent are obese (which is defined as being at least 20 percent over the desirable weight range for one's height, with fat constituting 30 percent or more of the body in women and 25 percent or more in men). The U.S. obesity figure of 33 percent is up from a rate of 25 percent in

1980 and 24 percent in 1962.

Although no one knows exactly what the health hazards of obesity are, excess weight seems to be implicated in some 300,000 deaths a year.

Heart disease aside, there is overwhelming evidence that a high-fat diet increases the risk for cancers of the colon, breast, and prostate.

More significantly, excess weight prevents a person from extending his or her life, and contributes to many of the diseases of aging: high blood pressure, heart disease, stroke, diabetes, cancer, digestive disorders, and gallbladder complications. High weight is correlated with high cholesterol, which in turn is a predictor of cardiovascular problems.

Fat in men tends to settle in the stomach, creating the so-called "apple" shape, whereas fat in women most often settles around the hips, giving over-weight women a "pear" shape. Men seem to be at higher risk for most obesity-related conditions than are women.

To determine whether your shape is dangerous to your health, measure your waist at its narrowest point and then measure your hips and buttocks at their widest point. Divide the waist measurement by the hip figure. If your waist-to-hip ratio is higher than .8 (for women) or .95 (for men), you probably need to lose weight.