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Garth Sundem

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Salk Study: Eating for Eight Hours Reduces Obesity and Diabetes Risk

Posted: 05/22/2012 5:13 pm

Let's get this out of the way: No one's recommending you sit down and eat for eight hours. But a Salk Institute study published in the journal Cell Metabolism, shows that if you condense the total time you eat each day to only eight hours -- say 8:00 a.m. to 4:00 p.m. -- you can prevent weight gain and reduce diabetes risk, without changing your total calorie consumption.

Again: if you eat exactly the calories you're currently eating, but squish the total time you eat into eight hours a day, you'll avoid packing on pounds and lower your risk of all sorts of metabolic badness including diabetes.

"Of course, the foods you eat matter," says Satchin Panda, Salk Institute researcher and the paper's senior author, "But we showed that when you eat is just as important as what."

The seeming magic of fitness without eating less hinges on the function of mitochondria in your liver. Among other things, these mitochondria process food, cycling through a defined schedule of work and rest. While they rest, mitochondria divide. And if you eat while they're dividing, you force them back to work -- disrupting their metabolic cycle and leading to a higher rate of DNA damage than in mitochondria that aren't bombarded by burritos when they're trying to get their division on.

At Salk, 8-hour feeding mice used nutrients more efficiently and had more energy than free-feeding mice. Astoundingly, the study writes that these 8-hour mice, were also "protected against obesity, hyperinsulinemia, hepatic steatosis, and inflammation and have improved motor coordination."

Despite the header of its Wikipedia entry encouraging readers not to confuse it with foie gras, hepatic steatosis or "fatty liver" is no joke.

"Our circadian clock separates functions throughout the day so that our organs stay healthy," says Panda. But the clock in your liver isn't a sundial -- it doesn't simply monitor lightness and darkness and click through its organ functions based on time of day. Instead, "it gets information about time by when we eat," says Panda. Your liver needs to know when you've taken your last bite of the evening so that it can tell mitochondria it's safe to divide. "And if you eat all the time, the clock gets the clue too many times, it tries to adjust too many times, and it never knows when it's breakfast," says Panda.

This forced adjustment of circadian rhythm and the resulting mitochondria damage is one reason that shift workers -- who are nocturnal on weekdays and then try to adjust to a diurnal schedule on weekends -- have 150 percent higher rates of metabolic disease than workers with standardized schedules of eating and sleeping.

And, Panda points out, with people in the United States now averaging more than 160 hours of TV viewing per month, "we have 100 to 120 million people who are social shift workers," he says. Led by the TV's silver tongue, Americans have made the social decision to act like shift workers. "And this population is more at risk for every type of metabolic disease," says Panda.

So don't be a social shift worker. Your mitochondria will thank you for it. And if you want to lose weight on your current high-fat diet, eat your calories in an eight-hour window.

 
 
 

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Let's get this out of the way: No one's recommending you sit down and eat for eight hours. But a Salk Institute study published in the journal Cell Metabolism, shows that if you condense the total tim...
Let's get this out of the way: No one's recommending you sit down and eat for eight hours. But a Salk Institute study published in the journal Cell Metabolism, shows that if you condense the total tim...
 
 
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HUFFPOST SUPER USER
dsws
No owning ideas. Limit only commercial use.
02:20 PM on 05/30/2012
Interesting. There are so many factors involved. I hadn't even thought of the possibility of liver mitochondria.
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HUFFPOST COMMUNITY MODERATOR
ConfuciusSay-
Aglets: their purpose is sinister.
01:18 AM on 05/25/2012
If I were a mouse, I'd be very excited.
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HUFFPOST SUPER USER
farmerlady
Blonde, Democratic socialist, and unwilling expat
09:42 AM on 05/24/2012
With my work schedule this is frankly impossible. Most of us work at least 8 hours a day and many of us work more. So how are we supposed to eat this way? I can't leave work for dinner before 4 p.m.

Sorry, won't work.
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HUFFPOST SUPER USER
Laura Cody
A New Dawn - I hope for change
01:42 PM on 05/26/2012
Those hours were only suggested. You could start your 8 hour clock at lunch.
07:29 PM on 05/23/2012
Wow, I can't believe he skipped over the fact that this study was done on mice. We all love the idea that we can eat normally and lose weight, but I think I'll wait until HUMAN trials are done. Please Huff vet your bloggers better or at least make sure they mention the big stuff (testing on mice) up front.
01:08 AM on 05/25/2012
Read it again. The testing of mice was clearly stated.
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HUFFPOST SUPER USER
Deadliftmcgee
10:27 AM on 05/23/2012
This pretty much describes Intermittent Fasting, which I have been doing for a year, and which is picking up steam in the fitness community. While doing IF, I got leaner than I have ever been, and didn't really suffer from the constant hunger of diet. Quite the opposite, I fast for 16 or 18 hours, then eat large, satisfying meals, and still stay under my caloric limit.

There are numerous resources out there citing the benefits of IF, but here are a few:

- Burn more stored fat for a longer period of time, since you give your body time to deplete its glycogen stores.
- Increase levels of human growth hormone, testosterone, adrenaline and noradrenaline (all of which contribute to fat burning)
- Increases insulin sensitivity
- Personally, your food tastes better after not eating for 16 or 18 hours.

Research like this is a first step, but, as with anything, do what works for you.
noahmarder
Exposing the regressive lies, one by one
02:57 AM on 05/25/2012
We seem to be on the same side of most fitness issues, but I'm really wondering how you manage to eat enough food to accommodate your weight lifting if you only eat within a six to eight hour window per day.

I don't know what your daily caloric intake is, but there's no way I could get my 4,000 inside of eight hours without absolutely stuffing myself and/or eating too much fat and not enough protein.
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babybelle
EARTH without art is just EH
06:48 AM on 05/30/2012
I do IF too, but my longest fast is 13 to 14 hours.
I was never obese, but went from 125 to 102 which I have maintained.
I am 65 years old and never felt better !
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badders
Bad taste creates many more millionaires than good
08:30 AM on 05/23/2012
Why not a 7 hour window or 9? How did they reach the magic number 8?

Allow me to be blunt. This is bullsh*t. Eat what you want and don't worry about exercise, because some scientists ran a test on a few mice? It's science. Mitochondria, hepatic steatosis, circadian rhythms, oh my!

People, this is nonsense. HP should be ashamed.
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Laura Cody
A New Dawn - I hope for change
01:46 PM on 05/26/2012
Just to confuse things there is also an intermittent fasting diet called Fast 5 where you choose 5 consecutive hours to eat in. I have known quite a few people that do this and I have done it myself but had other issues which, well anyway, had to stop. Once I sort out the issues, I am going to give intermittent fasting another go.
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babybelle
EARTH without art is just EH
06:55 AM on 05/30/2012
For me, IF eating 3 meals a day. No snacking between meals.
The longest I go without food is between dinner and breakfast.
It works great from me.
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Laura Cody
A New Dawn - I hope for change
07:39 AM on 05/30/2012
No its not bull... there is quite a bit a science behind fasting and not just in mice, but in humans.
08:07 AM on 05/23/2012
When you go behind politics we see that type 2 diabetes has already been reversed. Dr Liu in Denmark revealed how to reverse diabetes without any medications. No one needs a drug to reverse type 2 diabetes.

All of this information was taken from the Spirit Happy Diet people in Denmark. Diabetes has been reversed in over 10,000 people by using a specialized diabetes diet. The diet also reversed body fat in people trying to lose weight. Scientists showed food chemicals is the cause of almost all diabetes. They also showed how to reverse your own diabetes without medications. This was shown in Denmark here http://spirithappy.org
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NotEve
Facts are of no use against the irrational
12:53 PM on 05/28/2012
You don't need to go all the way to Denmark or read about yet another fad diet ("spirit happy" or not). It's common knowledge among healthcare professionals that diabetes is best treated, and often reversed, through diet and exercise. The problem is compliance. Even though diet and exercise are the first line of treatment for type 2, any treatment that your patients ignore is ineffective.
ThinkCreeps
Seriously, it's time.
05:47 PM on 05/22/2012
Almost as much as a bit of self-respect and moderation.