Calorie restriction disappoints in longevity and quality of life
Diet composition and fitness trump (severe) calorie restriction in benefits
You would think that all of us, if given a choice, would want to live longer. However, in a recent informal survey involving 30,000 participants over the last three years, more than half did not want to live past the 80-year current life expectancy for developed countries (NYTimes.com Aug. 25). This would be surprising, except that the most frequent reason offered had to do with not wanting to be old and debilitated. What if we could propose improving longevity — and health — so that people would feel vivacious throughout their lives, regardless of age?
Calorie restriction impact
Recent thinking has been that if we restrict our calorie intake significantly, by 30 percent, then we are more apt to live longer and healthier lives. That is what we were led to believe by earlier studies in monkeys, like the 2009 University of Wisconsin study (Science. 2009 Jul 10;325(5937):201-4). The problem with the study was that the researchers discounted a number of monkeys who died, claiming this did not have to due with aging.
However, a newly published study with rhesus monkeys reported different results (Nature online Aug. 29). Severely restricting these monkeys’ calories did not increase their longevity, nor did they live healthier lives. These results were disappointing in that calorie restriction is not necessarily the panacea that we thought. This was a 25-year study and the results had been eagerly anticipated.
There were some benefits to calorie restriction, though. For older males and females, heart disease risk was reduced due to lowered triglyceride levels. This was true, ironically, only when calorie restriction was begun when the monkeys were already old.
However, the monkeys — calorie restricted or not — did still experience chronic diseases such as heart disease and cancer.
What about chronic disease?
It appears that chronic disease is the greatest hindrance to achieving or maintaining a better quality of life. Coincidently, the Centers for Disease Control and Prevention has released data that show chronic disease is on the rise, with increasing numbers of patients having two or more diseases. Also, it appears that the United States lags behind European nations in reducing the number of preventable deaths, called “amenable mortality.” Most of these deaths are caused by chronic disorders, such as high blood pressure, stroke and cancers. The U.S. is seeing a decline in its rates of preventable deaths but at half the pace of France and the United Kingdom. So what can we do to slow the rise in chronic disease and accelerate the decrease in our rate of preventable deaths?
Diet composition effect
Dietary choices can have a tremendous effect on health. Not surprisingly, poor diet composition is one of the leading contributors to many chronic diseases such as high cholesterol, diabetes and heart disease, and thus amenable mortality rates (Ann Intern Med 2010;153:736-750). The CDC showed that only about one-quarter of Americans consumed the most basic levels of fruits and vegetables recommended.
However, there are several diets that have been promoted because they are known to have powerful effects on reversing this dismal trend of increasing chronic disease such as the DASH diet and the Mediterranean-type diet. In 2010, the DASH diet was highlighted because of its beneficial effects on prevention and treatment of disease (www.cnpp.usda.gov). At the basis of this diet is the emphasis on nutrient-rich foods, including fruits, vegetables, nuts and seeds, beans and legumes, and whole grains, as well as a modest amount of lean animal protein.
The DASH diet was originally designed to lower blood pressure. In a randomized controlled trial, the gold standard of studies, DASH showed significantly lower systolic blood pressure results compared to those on a standard diet, even though both groups were intentionally given the same level of sodium intake, which is very interesting (N Engl J Med 1997;336:1117-1124). The difference was that DASH increased the amounts of fruits, vegetables and low-fat dairy, while lowering saturated fat.
Subsequent prospective studies, such as the Nurses’ Health Study, have borne out the benefits of the DASH diet in lowering heart disease risk in patients followed for a 25-year duration (Arch Intern Med 2008;168:713-720).
Fitness at any age — a greater impact than expected
We used to think that fitness helped delay disease, but a new study suggests that fitness in middle age, defined as people in their 50s, actually decreased the risk of chronic disease significantly. It didn’t just delay it (Arch Int. Med online Aug. 27). Ultimately, fitness at any age seems to provide us with a higher quality of life. This study involved 18,600 participants. There was an approximately 45 percent reduction across the board for both men and women in incidence of the top eight chronic diseases.
The good news is that you may not have to make yourself miserable by eating a very low calorie diet in the hopes of achieving a longer life.
Rather than suffering — or imagining suffering — through severe calorie restriction, why not focus on consistent, modest fitness routines and diets that are rich in nutrients and high in volume? The potential disease-modifying effects could play a crucial role in preventing what we perceive as age-related decline. Then, you can have a positive attitude toward living longer, since you will be able to maintain, if not improve, your health as you age.
Dr. Dunaief is a speaker, author and local lifestyle medicine physician focusing on the integration of medicine, nutrition, fitness and stress management. For further information, go to the website www.medicalcompassmd.com and/or consult your personal physician.