Calm and Well: Does Calorie Restriction Lead to Increased Lifespan?

(photo from NY Times)

There doesn't seem to be a wealth of information on increasing lifespan. I have always found it surprising that more research hasn't been done on the slowing of the aging process. I think that most people consider aging and decreasing levels of mental and physical functioning, inevitable consequences of life. My main motivation for this blog and my pursuit of health is to live a longer, healthier life, so this subject is very important to me.

Unless I am mistaken (if so, please alert me!), the only scientifically proven way to extend life is through calorie restriction. It has been found across many different animals (rats, mice, primates, spiders) that a 10-30% caloric reduction leads to longer life and reduced health problems. In fact, according to animal studies, the higher the amount of calorie restriction and the earlier it is implemented, the longer life can be extended (http://legacy.signonsandiego.com/news/science/20041124-9999-lz1c24cr.html).

(graph from of www.iangoddard.com)

The money question is whether calorie restriction animal studies can translate to humans. Personally, I don't see why it wouldn't, but for worldwide recognition, more research needs to be done. We have seen the dangers of obesity and the health benefits of eating fewer calories, so it isn't a huge leap in thought to think that calorie restriction may extend lifespan. There is evidence that lower body weight is associated with less disease and increased longevity, and since eating less is associated with lower body weight, it isn't far off to group calorie restriction with those ideas (http://www.iangoddard.com/cr.html).

It also makes sense on an evolutionary level. We have not evolved since we became modern human beings. This means that we live in a modern society, but our bodies are still adapted for a prehistoric world. We evolved during a period of time when starvation and disease were a daily threat. We now have tons of food, materials, and goods, but our bodies are still made to deal with starvation and lack of materials. In this way, overconsumption becomes the enemy.

How restricted is it?

The average human consumes about 2000-2500 calories a day, so a 30% reduction would be 1400-1750 calories a day. Sounds pretty restricted, doesn't it? The important (and difficult) thing to remember is that this is a change in lifestyle, not a temporary fad diet plan. Luckily, there are supportive books and websites for those trying to implement calorie restriction into their lives.

Recommended Websites

Calorie Restriction Society International

The Longevity Meme

Recommended Books

The Longevity Diet (by CR Society President Brian M. Delaney and Emeritus Board member Lisa Walford)

Beyond the 120 Year Diet: How to Double Your Vital Years

The CR Way: Using the Secrets of Calorie Restriction for a Longer, Healthier Life

The Benefits?

In Laboratory animals, aside from increased lifespan, calorie restriction has also been linked with a reduction in:

- Cancer

- Heart Disease

- Diabetes

- Osteoporosis

- Autoimmune disorders

- Neurological decline

- Alzheimer's

- Parkinson's

(see below for associated research)

I am intrigued by all of this information. I'm not sure I would be able to forgo that many calories on a daily basis, but it is still important information. Eating a well-balanced diet and getting plenty of exercise also go far. As a compromise, it might be a good idea to fast every now and then. When we fast (or reduce calories) we redirect our body's forces to repair, detoxification, and renewal. Maybe a healthy diet combined with an occasional fast can accomplish as much as long-term calorie restriction.

An important note: You should never implement any type of severe diet without consulting your doctor or health professional. Also, it is important to keep in mind that even though calories are restricted, it is mandatory that healthy food be eaten, along with enough vitamins/protein/minerals. A generous handful of cheese-its 3 times a day, resulting in 1500 calories is not going to cut it! :)

Publications

Cancer

Kritchevsky D, & Klurfeld DM. (1986). Influence of caloric intake on experimental carcinogenesis: a review. Advances in Experimental Medicine & Biology, 206, pages 55-68.

Albanes D. (1987) Caloric intake, body weight, and cancer: a review. Nutrition & Cancer, 9(4), pages 199-217.

Kritchevsky D. (1997). Caloric restriction and experimental mammary carcinogenesis. Breast Cancer Research & Treatment, Nov-Dec, 46(2-3), pages 161-7.

Kritchevsky D. (2001). Caloric restriction and cancer. Journal of Nutritional Science and Vitaminology (Tokyo). February, 47(1), page 13-9.

Heart Disease

Swoap SJ. (2001). Altered leptin signaling is sufficient, but not required, for hypotension associated with caloric restriction. American Journal of Physiology, Heart & Circulatory Physiology, December, 281(6):H2473-9.

Keenan KP, et al (1994). The effects of overfeeding and dietary restriction on Sprague-Dawley rat survival and early pathology biomarkers of aging. Toxicologic Pathology, May-June, 22(3), pages 300-15.

Diabetes

Stern JS, et at. (2001). Calorie restriction in obesity: prevention of kidney disease in rodents. Journal of Nutrition, March, 131(3), pages 913S-917S.

Fujioka K, et al (2000). Weight loss with sibutramine improves glycaemic control and other metabolic parameters in obese patients with type 2 diabetes mellitus. Diabetes, Obesity & Metabolism, June, 2(3), pages 175-87.