A Case For Intermittent Fasting

[Kasra]

I found a study that makes a compelling case for intermittent fasting:

Mice that were fed a high-fat diet developed obesity, hyperinsulinemia, hepatic steatosis, and inflammation.

Mice that were fed the same high-fat diet, but were restricted to an 8-hour feeding window, did not develop these symptoms. These mice ate the same total calories of the same high-fat food as the former group, yet remained lean and healthy.

The authors of the study attribute the benefits of the time-restricted feeding to a strengthening of metabolic/circadian rhythms. If nothing else, this study casts serious doubts on the "calories in, calories out" model of dieting and fat loss.

The full text is available here: http://www.sciencedirect.com/science/ar ... 3112001891

 

[Kasra]

Similar papers:

http://www.sciencedirect.com/science/ar ... 3114004987

http://www.fasebj.org/content/26/8/3493.short

 

[Amazoniac]

It's a great strategy but it has to be done properly. Since we store fats better than carbohydrates, we should be careful with our carbohydrate intake so that at the end of the fast we are starting to become depleted. When you get used to it, you become adjusted to that feeding window and you expect that food will be consumed, contrary to activating a starvation response and not knowing when will be the next meal, this is why I think you need some time of adjustement.

 

[Dean]

Amazoniac, so are you saying as a Peatish approach to this you would limit fats to this 8 hr. window or all eating? To me, your liver would have to be in pretty tip-top shape to eat the Peat way or Peat-like (high carb) and consume all of your calories within 8 hours.

 

[Amazoniac]

People that are healthier require less sleep, people that are ill require much more sleep and sometimes it's not enough to feel rested. Eating constantly is stressful in someway. To transform food in structure and energy is a strenuous process and you often compete for it in your intestines. There are losses, by-products and threats in the process. So digesting food is in someway toxic due to that. If you are able to restrict this process in a shorter feeding window, you are giving your organism a break to handle everything that's happened, reorganize. If you are feeding constantly, you don't give that break and it's not optimal. In my opinion, even if you are ill, restricting your feeding window is something you should aim for in the long-term. The exception in the short-term would be someone who are sick from too much calorie restriction and its associated diseases.

People noticed a long time ago that restricting calories prolongs life, the problem is that is easy to overdo it and difficult to reach a balance of providing enough nutrients but without excess. Eating a lot of calories will surely increase your metabolism, but that doesn't mean that it has become efficient. An efficient metabolism is when you don't have to exceed to reach optimal function.

 

[Amazoniac]

Amazoniac, so are you saying as a Peatish approach to this you would limit fats to this 8 hr. window or all eating? To me, your liver would have to be in pretty tip-top shape to eat the Peat way or Peat-like (high carb) and consume all of your calories within 8 hours.

Limit all food intake to a restricted feeding window.
Between your last meal and the usage of what you've stored, it takes longer than what it looks like. So, we are able to fast for a considerable time before activating a stress response to starvation.

 

[mt_dreams]

If the point of IF is to give your digestion a break, or rather utilize the energy needed for digestion towards other bodily functions, is it also possible to achieve this by eating only easily digestible foods? What would be the net effect of say eating lots of heavy foods (which is what I needed when I practiced IF a couple of years back) like pork, whole grains, legumes, etc, in a 4-8 hour window, compared to more easily digested foods like fruit,diary, & light fish spread throughout the day?

 

[Amazoniac]

In my opinion it's desirable to eat a mix of both, easy and hard to digest foods. Eating only rapid digested foods won't prolong the satiation of a meal that is digested steadly. It is also important to eat harder to digest food due to the fact that you don't have many calories delivered so fast to your organism. Otherwise, you'll have to eat constantly because you won't have that prolonged satiation effect after a meal.
And I don't think that fruit and dairy are digested that fast compared to the others you mentioned. White fish and fruit juices maybe..

 

[Amazoniac]

I also believe that in order to fast properly it's better to consume most of your calories from fat. Not very low-carb, but lower. Carbohydrates not only to supply enough nutrition for carbohydrate dependant functions, but also for storage to fast comfortably.
It's possible but harder on a higher carb diet.

 

[RPDiciple]

I want waste much time on this.. its all crap. IF is great for loosing fat and all the benefits that brings. Its not good if you are working towards optimal health.

 

[Dean]

I've experimented with ketogenic, vlc, paleo and other low-carb diets and read a lot about other people's experiences. I agree with what you say about digestion seemingly being stressful on the body; but I have read a lot of accounts of people who have used IF long term who developed metabolism issues. So, I'm not sure it is as simple as it seems. I also think there are questions about how much protein, for example, your body can utilize in one sitting or within a certain period. Perhaps that's what you were getting at when suggesting that IF would be most suitable for someone on a high fat/moderate to low protein and carb diet. It would appear to me to be not only "harder", but exceedingly difficult to use IF while "Peating,"

 

[Kasra]

Read the paper.

 

[Amazoniac]

Most of his perspectives apply to both higher and lower carb.
The metabolic issues that people develop in the long term may be due to lack of enough calories. It's very easy to not provide enough nutrition while practicing IF.
Also, a lot of people that practice IF are on VLC diets; which make the process very stressful. And in the long-term some metabolic issues arise.
I think you should supply at least 35% of your caloric intake from carbohydrates to fast properly. And if stressed, you probably are going to need more and fasting becomes harder.

 

[livrepensador]

Next week im going to try IF.
When i was a low carb i did it but i felt like crap. Today, im thinking that crap felling was due to low carb not due the IF.

I really need to drop some fat and despite Peat-eating make me more stress-free im stucked with a belly fat

Lets see what happens... my diet will consist 2 meals a day:

- Whole milk
- Sugar
- Whole oranges
- Meat
- Coke
- Some mashed potatoes
- Eggs

 

[Giraffe]

related topic: Even intermittent fasting reduces insulin sensitivity

 

[DrJ]

Unfortunately, the study seems to not have lasted very long: ~20 weeks. Not quite half a year. I came to Peating from doing IF, and my experience was that I felt great for about the first 6 months on IF. But after, that I did not. I attribute this to how long it took for me to acclimate to the stress hormones, cortisol and adrenaline. Can I prove this? Of course I cannot since I did not do blood tests.

What I do know is that after IF, my body temp was in the mid-to-low 95.xF, and I was cold all of the time. After Peating for over 18mo, I sit above at least 97.5F and usually above 98F, and feel much better; and this is without aspirin any more. I think it's safe to say after 18mo stress hormones are not the reason.

That said, I lost much weight on IF. I was lean and veiny. Now, I am lean and not veiny, but it took some time to figure out how to achieve this, and it was mainly by not eating too much fat (read: ice cream :)). But I prefer the Peat way because I am not cold, my energy levels are very constant from waking to sleeping, I sleep much better and wake naturally, and my mental clarity is substantially better. I would just warn anyone contemplating IF to consider that you might do significant damage to your metabolism, and in my case, it took about a year to fully correct.

 

[tara]

post 113262 Next week im going to try IF.

Do you have reason to think your glycogen storage is strong?
My impression is that this is what may distinguish people who can thrive on fewer meals.

I don't particularly recommend fasting much longer than a night's sleep, but if you are going to give it a go, there might be ways to make it less stressful. I'd consider experimenting with:
- Work up to in gradually. Eg. increase the time between meals by 1/2 hour or so every few days till you reach your target, and back off for a while if you can tell that it is stressful.
- Making those two meals breakfast and lunch. May not be the case for everyone, but I think many of us make better use of food in the morning and during the day than later in the evening. (I'm influenced by RBTI and my own experience here.)
- Make sure to eat at least to appetite in those two meals.
- If you have more trouble sleeping, allow yourself something light in the early evening as well, eg some orange/juice or milk. .

 

[EIRE24]

post 113273 Unfortunately, the study seems to not have lasted very long: ~20 weeks. Not quite half a year. I came to Peating from doing IF, and my experience was that I felt great for about the first 6 months on IF. But after, that I did not. I attribute this to how long it took for me to acclimate to the stress hormones, cortisol and adrenaline. Can I prove this? Of course I cannot since I did not do blood tests.

What I do know is that after IF, my body temp was in the mid-to-low 95.xF, and I was cold all of the time. After Peating for over 18mo, I sit above at least 97.5F and usually above 98F, and feel much better; and this is without aspirin any more. I think it's safe to say after 18mo stress hormones are not the reason.

That said, I lost much weight on IF. I was lean and veiny. Now, I am lean and not veiny, but it took some time to figure out how to achieve this, and it was mainly by not eating too much fat (read: ice cream :)). But I prefer the Peat way because I am not cold, my energy levels are very constant from waking to sleeping, I sleep much better and wake naturally, and my mental clarity is substantially better. I would just warn anyone contemplating IF to consider that you might do significant damage to your metabolism, and in my case, it took about a year to fully correct.

What did you do to recover and what kind of foods do you eat now? I am in a similar situation so it would be very helpful to me?

 

[livrepensador]

post 113262 Next week im going to try IF.

Do you have reason to think your glycogen storage is strong?
My impression is that this is what may distinguish people who can thrive on fewer meals.

I don't particularly recommend fasting much longer than a night's sleep, but if you are going to give it a go, there might be ways to make it less stressful. I'd consider experimenting with:
- Work up to in gradually. Eg. increase the time between meals by 1/2 hour or so every few days till you reach your target, and back off for a while if you can tell that it is stressful.
- Making those two meals breakfast and lunch. May not be the case for everyone, but I think many of us make better use of food in the morning and during the day than later in the evening. (I'm influenced by RBTI and my own experience here.)
- Make sure to eat at least to appetite in those two meals.
- If you have more trouble sleeping, allow yourself something light in the early evening as well, eg some orange/juice or milk. .

Hey tara! Thanks for the great ideas..... but the DrJ´s post made think twice.
My sleep is way better than 9 months ago. My energy levels is really good and so my mood.
Despite of im being a little overweight, im not risking IF again.
I think it would be a better approuch try to eat less calories..... i have a good trick to do this: chew a LOT the food. I think i will try this technique for a few weeks. Some years ago i did it and lost a good amount of weight.

DrJ, i am curious too about the EIRE24 question. Please give us some directions?

Thanks everybody!

 

[tara]

post 113491 Despite of im being a little overweight, im not risking IF again.

That sounds wise to me.

post 113491 My sleep is way better than 9 months ago. My energy levels is really good and so my mood.

That's worth a lot. Don't throw it way by going too low in calories for too long.