Why and How – Intermittent Fasting




Putting more hours between dinner and breakfast may stave off obesity, at least in mice. This according to biologist Satchin Panda, and his colleagues at the Salk Institute in La Jolla, California. His team studied mice on high-fat diets. One group was allowed to eat freely at all times, and became obese and unhealthy. But another group, which ate the same number of daily calories as the first group—but within a strict eight-hour window—fared better.

Surprisingly, the mice that were eating the same number of calories, but ate only for eight hours, did not become as obese as the first group. Less than 12 percent of their body weight was fat, as opposed to 40 percent. That group’s cholesterol, blood sugar, and liver function were all nearly normal as well. Panda says that modern society’s late-night dining and snacking may be contributing to the obesity epidemic.

The results, published December 2, 2014 in the journal Cell Metabolism, add to mounting evidence suggesting that it’s not just what we eat but when we eat it that matters to our health. Although the intervention has not yet been tested in humans, it has already gained visibility as a potential weight loss method–and, in mice, it may reveal what causes obesity and related conditions in the first place.



In the study, the mice were  divided into two groups, with each group then being divided again into two more groups. Stay with me. Half the mice were fed a diet with 60 percent of its calories from fat, while the other half, a control group, ate normal, healthy food. Within each of those groups, half the mice ate on an unrestricted schedule, while the other half were allowed to eat only within an eight-hour window.

High Fat Diet Group                          Healthy Diet Group

Half ate 24/7                                       Half ate 24/7

Half 8 hour window                           Half 8 hour window

**According to the researchers, those mice quickly learned that food was available only at certain times, and consumed all the food they were given within that time period**

After 100 days, the differences in mice on the high-fat diet were obvious. Those that ate whenever they wanted gained weight and developed high cholesterol, high blood glucose, liver damage, and impaired motor control. However, the mice that ate the same high-fat diet with the same daily calories but during a short feeding time fared much better. They weighed 28 percent less than the free-feeding mice (in a human, for example, that’s the difference between 200 pounds and 144 pounds). In addition, they did not substantially show any of the ill health effects that went along with the weight gain. For example, on an exercise test they outperformed not just the overweight mice but also those that had been fed a normal diet.

“It’s an interesting observation that although the mice on a normal diet did not lose weight, they changed their body composition,” Panda says. “That brings up the question—what happens? Are these mice maintaining their muscle mass which might have been lost with free feeding, or are they gaining muscle mass?”

Using this new experimental set-up–with genetically identical mice consuming equal amounts of a given diet, just within different time windows–gives the researchers a tool to delve further into the causes of diabetes, Panda says.

A comprehensive analysis of the blood metabolites in time-restricted mice revealed that multiple molecular pathways that go awry in metabolic disease are turned back to normal and protective pathways are dialed up, Chaix adds. Next steps include looking more in-depth at these pathways, as well as investigating the effects of time-restricted eating in humans. https://www.salk.edu/news-release/another-case-against-the-midnight-snack/

According to the researchers, constant eating may deprive our bodies of an important chance to maintain itself. While we eat, the body stores fat, which adds weight and puts stress on the liver, and produces glucose, which elevates blood sugar levels—a sign of diabetes. In contrast, evidence suggests that when we stop eating for several hours, the liver stops releasing glucose into the blood, and instead uses it to repair cellular damage. It also releases enzymes that break down cholesterol into acids, which in turn help break down brown fat—a “good” fat that converts calories into heat.


Benefits of an 8 to 12 hour eating window:

Corrected insulin sensitivity and metabolism

Body gets a chance to perform other vital functions (regenerate, renew, replenish)

Increase in lean body mass, decrease in fat mass

Improved cholesterol, blood pressure and liver health

Read more here:http://www.mercola.com/infographics/intermittent-fasting.htm