By Dr. Joseph Mercola
with Rachael Droege
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Numerous studies have shown that lowering your caloric intakemay slow down aging, reduce age-related chronic diseases andextend lifespan. The effects have been observed in a varietyof species from worms and yeast to rats and fish, and whileit is uncertain whether long-term calorie restriction hasthe same effect in humans, preliminary evidence suggests thatit does.
What is known is that calorie restriction reduces metabolicrate and oxidative stress, improves insulin sensitivity, andalters neuroendocrine and sympathetic nervous system functionin animals, as noted in a review in the AmericanJournal of Clinical Nutrition. The mechanism behind theseeffects is not known, but I suspect the majority of the benefitsfrom calorie restriction are related to its influence on insulin,as reducing calories also reduces insulin, a major accelerantof aging. Insulin also affects many bodily systems, all ofwhich could potentially affect longevity. Insulin:
- Alters the expression of numerous other hormones
- Stimulates the sympathetic nervous system
- Promotes vasoconstriction
I do believe that eating less is likely to be healthier forus in the long run, as controlled energy restriction is theonly regimen that has been shown in the laboratory to increaselifespan, and therefore may be a foundational requirementfor proper diet. Calorie restriction is not the same thingas dieting or starving yourself, however, so please realizethat this can't be done without wisdom as human populationsthat consume low-calorie diets that are restricted in proteinand micronutrients have:
- Short stature
- Late reproductive maturation
- Suppressed ovarian function
- Impaired breastfeeding
- Impaired fertility
- Impaired immune function
Fortunately, many of the above side effects can be avoidedby using more nutrient-dense food sources. This is one ofthe reasons why the juicingprogram works so well. It provides relatively low-calorie,dense nutrition that does not raise insulin levels. Anothergreat whole food option is whey protein concentrate , which provides dense nutrition with low caloriesand a minimal insulin response, and is very convenient forthose who are often on the go.
Calorie restriction won't work if you aren't gettingenough vitamins, minerals and other nutrients that are necessaryto keep your body functioning properly. Inadequate nutritionwill result in malnutrition and a worsening of health. Soif you do decide to control your calories, make sure thatevery calorie you eat comes from a nutrient-rich food source.
It isn't necessary to use an all-or-nothing approachto calorie restriction as studies have shown that minor tomoderate calorie restriction can result in some health benefitsalso. It appears that the more calorie restriction, the greaterthe health benefits, unless you become undernourished.
While an extreme calorie-restricted diet is not appropriatefor some people, merely cutting out junk foods and soda, whichare virtually all high in calories, could result in moderatecalorie restriction and provide a great deal of health benefits.Occasionally skipping lunch or eating smaller meals, especiallywhen only unhealthy foods are available, is also likely toprovide some benefit.
If you are interested in this way of eating, check out mynutrition plan for advice onfoods that are rich in nutrients and health-promoting properties.Please note that calorie restriction is not appropriate forchildren under the age of 21 years, pregnant or nursing women,or women who are trying to conceive.
Interestingly, it is thought that exercisemay also create a "relative" calorie restrictionas exercise produces many of the same benefits such as:
- Improved insulin sensitivity
- Decreased fat mass (FM)
- Reduced cancers
When you think of calorie restriction, think of minimizingyour intake of calories and harmful substances while maximizingyour intake of nutrients. Anyone who tries calorie restrictionshould carefully monitor their health and watch for potentialside effects such as decreased bone density, feeling faintor overly fatigued, decreased mood or sex drive and an increasedsensitivity to cold temperatures.