The benefits of fasting

I have always dismissed the idea of fasting as kind of faddish and new agey. Plus self-denial doesn’t appeal to me. As far as I know, people mostly choose to fast for weight control. (One 456-pound man fasted for more than a year and lost 276 pounds.) But I’ve just found some interesting research that shows other health benefits of withholding food.

Because we probably evolved to endure periodic bouts of starvation, our organ systems may be programmed to function optimally in intermittent fasting-type conditions. At the very least, our early ancestors’ eating patterns were probably restricted to the daylight hours. Now we eat all the time—night and day, probably throwing off some delicate mechanisms. (One of the mechanisms has to do killing damaged cells and replacing the dead cells with newly regenerated cells.)

Here are the benefits, way over-simplified here (the mechanisms that cause these effects are wildly complicated, some having to do with gene expression and altering metabolic pathways):

• Liver: increases insulin sensitivity, decreases insulin resistance, lowers blood glucose levels. Also, the liver’s glycogen stores become depleted and our bodies start burning visceral fat.
• Immune system: reprograms T-cell populations, tamping down autoimmunity; also reduces pro-inflammatory substances.
• Heart: lowers blood lipid levels and blood pressure.
• Brain: improves memory, learning, and neuron repair.

Fasting regimens vary, such as every other day, two days a week, or periodic, such as once a month or once a year. But there’s also one called “time-restricted feeding”: you confine eating to a window of 8, 10, or 12 hours a day. How hard is that? At our house we do that all the time: we eat dinner at 5:30 (we’re old) and break our fast at 7:00 in the morning. That’s easily 12 hours of fasting. It counts!

So wait a minute. Most of us fast every day without thinking about it. Forget I said anything (although it's nice to know that our bodies put our fasting periods to good use; also that you don't have to go to any extremes to get the benefits).

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