Have you heard of the Longevity Diet or Calorie Restriction Diet? It's been in and out of nutrition news for many years, the theory and related research starting in the 1930s. The concept is that by eating less total calories and ensuring that the calories we do eat are highly nutritious, we can extend our life span. So what's the science behind this? No one knows exactly, but the research is growing, and so are the numbers of people trying it out.

In the 1930s, researchers studying growth patterns and food deprivation in mice noticed that adult mice that were underfed lived much longer than their well fed counterparts. Since then, there have been studies done on different animals, including primates, with basically the same results: those animals that were fed much fewer "high quality" calories lived longer and had better overall health.

Do you remember Biosphere 2? It was the project where they built a sealed, self-contained facility in Arizona and people lived there for 2 years. Well, the food production part of the experiment didn't go so well yet the participants stayed anyway. It was observed that although they became very thin, their health profiles (particularly the biomarkers of aging: cholesterol, blood sugar and c-reactive protein/inflammation) improved considerably.

This led to the formation of the Calorie Restriction Society by one of the Biosphere 2 members, Dr. Roy Walford. The society aims to raise money for research as well as to educate people on the benefits and risks of Calorie Restriction as a lifestyle. They have renamed the concept: Calorie Restriction with Optimal Nutrition. This is an important distinction, because if one restricts their calories from between 10 to 30%, it is imperative that what is eaten is high quality in terms of nutrition. No junk food allowed!

What have researchers found are the benefits of Calorie Restriction with Optimal Nutrition? Well, in humans it's not an easy research study to design because we live so long and there aren't many people willing to go to such extremes. But there have been some interesting findings.

This year, a research group studied 25 members of the Calorie Restriction Society (aged 41-65) who had been following the lifestyle eating 1400 to 2000 calories per day for an average of 6 years, along with another 25 people who had been eating "normal" American diet of 2,000 to 3,000 calories per day. They measured the diastolic function of all of them. This is a biomarker of age in hearts. The calorie restrictor's diastolic readings were of people 15 years younger.

One research group has been able to prove that calorie restriction in mice slows down death rates, particularly of cancer and kidney failure. Well fed, sedentary lab rats commonly die of these afflictions. They demonstrated that calorie restriction slows down the growth speed of breast, skin and white blood cells... which means a slower tumor growth rate.

One researcher is studying the implications of the fact that calorie restriction lowers the levels of insulin and insulin growth factor ?another cancer trigger. This also can't be bad in the fight for diabetes prevention and control!

And yet another research group is studying the idea that slowing down the amount of energy given to the mitochondria of our cells gives us fewer free radicals (cellular respiration generates free radicals). Hmm... many of us are taking anti-oxidant vitamins to combat free radical damage ? maybe we just need to eat less.

Although the concept really hasn't been studied enough to lend concrete answers, it deserves the attention of those of us who are looking to live longer and more productive lives. Many of the principles put forth by this lifestyle, such as to eat more nutrient dense foods (veggies, fruits, lean dairy, fish, lean meats and whole grains) and eat fewer empty calories (sugar, white flour, white rice and other processed foods), couldn't be bad for anyone!

It's pretty obvious that being overweight is a risk factor for a shortened lifespan, so why wouldn't being mildly underweight lengthen lifespan? It's an idea well worth consideration.

To find out more, check out the Calorie Restriction Society web site at http://www.calorierestriction.org/.

Copyright (c) 2007 Ainsley Laing