What changes occur in rats that are on a calorie-restricted diet?

Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)
The early rodent studies that showed that rats lived longer while consuming a calorie restricted diet showed some of the inner working of their biology. Over the millennia, rats have developed a three-pronged approach for not only surviving life's little surprises but turning them to their advantage. When a food shortage hits, here's what rats bodies do:
  • Establish priorities: Reproduction is at the top of the to-do list for all species—even rats. Correctly calculating that it will be hard to produce healthy little rats during stressful times, the rats' genes preprogrammed the rats to shut down all efforts to reproduce if even the slightest sign of impending stress was detected. Although the rats' energy had come back, they suddenly realized they had all but lost their interest in sex. No dating, much less mating (and sales of Yanni CDs plummeted). The rats were definitely living longer, they just weren't making any more rats. As if you didn't know already, reproduction takes a lot of energy, and during stressful times, that energy can be more productively used elsewhere, which leads us to the second prong of the longevity trident.
  • Keep up routine maintenance: Energy "saved" from delayed reproduction can now be put to work ensuring that maintenance levels are optimal. Live efficiently now to ensure you can live vigorously later on.
  • Focus on fuel efficiency: When the rats' calories are cut back, they start relying more on fat stores as a fuel source. Since fat combustion is several times as efficient at producing ATP than burning glucose, the same amount of energy can be created with much lower levels of free radicals. Fewer free radicals mean lower levels of free-radical damage, particularly to the mitochondria. Recent studies have shown that a calorie restriction of 40 percent leads to a 45 percent decrease in the rate of mitochondrial free-radical generation and a 30 percent reduction in the level of oxidative damage to mitochondrial DNA. The net effect of these changes decreases the rate of aging by about 50 percent.
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You: Staying Young: The Owner's Manual for Extending Your Warranty

International bestselling authors of YOU: The Owner's Manual and YOU: On a Diet give you all the tools and know-how to stay young and defy the ageing process. Drawing lively parallels between your...

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