Why Should You Reduce Your Caloric Intake?

Why Should You Reduce Your Caloric Intake?

Ponce de León was not alone in his search for the mythical Fountain of Youth. Increasing lifespan, and “healthspan,” has become a cultural obsession, fueling billion-dollar nutrition and fitness industries while firing the public imagination with its seductive promise. Paradoxically, as we learn more about aging, the goal of delaying it seems to remain tantalizingly beyond our grasp.

Can anything slow aging?

In a word, maybe! Several lifestyle modifications have been linked to a longer and healthier life. Among the most thoroughly researched are:

  1. Eating a Mediterranean diet rich in nuts, fruits, vegetables, fish, and olive oil.
  2. Engaging in moderate activity — think brisk walking — 150 to 300 minutes per week; above 300, life extension benefits rise more slowly.
  3. Having close-knit relationships with others.
  4. Caloric restriction (CR).

So eating less makes a person live longer?

Yes, circumstantial evidence suggests CR may add to both lifespan and healthspan. Proponents of CR point to the long lives of Okinawa’s population, where centenarians are relatively common. The traditional Okinawan diet is low in calories; since metabolizing food into energy generates free radicals that accelerate aging, a low-calorie diet may extend lifespan by reducing oxidative stress.

Before I cut my calories, I need more evidence!

CR studies have been conducted on yeast, worms, rats, and primates with much the same results  — a substantial increase in lifespan! Even though restricting food intake in humans raises ethical and legal issues, members of the CR Society believe strongly enough in the medical value of eating less to voluntarily cut their daily maintenance calories by 25% over the long term. That choice also places a premium on eating nutrient-dense foods without exception.

What results have loyal CR practitioners noticed? Body fat averages 6.7% in men. LDL cholesterol is markedly lower, and HDL notably higher. Blood glucose and insulin levels are sharply lower, and insulin resistance nonexistent. Blood pressure averages 100/60. C-reactive protein, a marker for systemic inflammation, is very low. Arteries are less stiff and heart function typical of adults 10-20 years younger. Similar results have been observed in studies of other species.

Are you telling me cutting calories 25% or more may also reduce the risk of chronic disease?

Yes, and that conclusion is no longer controversial. Several studies confirm a strong correlation between eating less and lower risk of:

  • Heart disease
  • Several cancers, including breast and prostate malignancies
  • Metabolic syndrome
  • Diabetes and insulin resistance
  • Arthritis

All of this evidence points to an improvement in healthspan, but the elusive object of Ponce de León’s quest rests on a less certain foundation. It could be argued, with some support, that the diseases of civilization CR addresses could, if minimized, amount to a major increase in average lifespan; certainly the CR Society’s biomarkers were all youthful.

But I’ll always be hungry!

Perhaps. However, scientists have identified genes that are turned on by CR and are beginning to identify substances — CR mimetics like resveratrol — that simulate the healthy effects of diminished calories. Promising new reports suggest that many of the benefits of CR can be achieved through intermittent fasting. We may not know for a century or more whether human subjects who practice CR live longer, but in the meantime we will most assuredly hunger for definitive answers.