2

votes

How long must you IF to reap the benefits?

Answered on August 19, 2014
Created November 29, 2011 at 6:38 PM

I'm interested in trying intermittent fasting by skipping a meal a few times a week. I wonder how many hours one needs to go food-free in order to reap the benefits of IF. Thanks everyone!

Ba20b502cf02b5513ea8c4bb2740d8cb

(1669)

on December 06, 2011
at 06:37 PM

Yeah I guess taking a gram of Fish Oil would be considered "breaking a fast" as well; I guess what you call what I'm doing is a decreased caloric intake for 24 hours supplementing with a greens drink. I don't fast for the sake of fasting or losing weight; Doing it for other reasons.

76c885d7d27e6c83542ea493ca866dcd

(2178)

on December 05, 2011
at 09:42 PM

I thought that ingesting anything but water broke a fast. doesn't having your SuperGreens drink break that up?

F44b15b2fd1ad134200793d6b474fc4c

(938)

on December 03, 2011
at 04:22 PM

Thanks for the detailed info, SSD.

F44b15b2fd1ad134200793d6b474fc4c

(938)

on December 03, 2011
at 04:20 PM

Thanks so much for the info and for the link, Wisper.

Medium avatar

(8239)

on December 03, 2011
at 04:56 AM

Thanks for being so specific about your regimen, SDD. I'm doing the Berkhan plan for a 3-month period. At the end I may revise in the direction of your protocol.

Ba20b502cf02b5513ea8c4bb2740d8cb

(1669)

on December 02, 2011
at 11:54 PM

Yeah I could see that due to the fact that binge eaters are having some serious insulin highs and lows and IF might mititgae that a little...

96bf58d8c6bd492dc5b8ae46203fe247

(37227)

on December 02, 2011
at 05:18 PM

I think the way to start is to have a nice large meal and then see how long it takes to get hungry. Over time, that interval may very well increase on its own.

96bf58d8c6bd492dc5b8ae46203fe247

(37227)

on December 02, 2011
at 05:17 PM

I have to disagree on not recommending IF for eating disorders and/or obese. I am a binge eater and started IF with at least 70 pounds still to lose. It's now 30-40 to lose, I'm losing the apple shape, and IF is the reason I'm succeeding. Others on PH have reported equally good results.

96bf58d8c6bd492dc5b8ae46203fe247

(37227)

on December 02, 2011
at 05:15 PM

Working out fasted is a good test to see if you've fully adapted to releasing/burning stored fat. Better luck on your next try!

9f54852ea376e8e416356f547611e052

(2957)

on December 02, 2011
at 04:07 PM

Plenty of them, google it. Martin Berkhan's 10 fallacies is a good place to start.

96440612cf0fcf366bf5ad8f776fca84

(19463)

on December 02, 2011
at 10:51 AM

Autophagy for one.

25b139cc1954456d9ea469e40f984cd3

on December 02, 2011
at 05:18 AM

What benefits?????????????????????????

Ba20b502cf02b5513ea8c4bb2740d8cb

(1669)

on December 02, 2011
at 04:46 AM

I'm the exact opposite; after the 16th hour I'm basically not thinking about food.

B4e1fa6a8cf43d2b69d97a99dfca262c

(10255)

on November 29, 2011
at 10:49 PM

2 day fasts once a week assisted in my initial weight loss when i was still SAD. the 2nd day was never pretty.

9f54852ea376e8e416356f547611e052

(2957)

on November 29, 2011
at 10:17 PM

It takes a while to get used to. I work out fasted, except for some BCAAs right before the workout. Heavy lifting, though, no cardio. The first time I did it wasn't too encouraging, now I have no issues.

94a4a87e3d2e1e9160b6ed77678b4bea

(1311)

on November 29, 2011
at 09:56 PM

+1 for HANGRY - Love it!

775bc83a7c54975e77a8500e065a24c3

(814)

on November 29, 2011
at 09:11 PM

Thanks for the link.

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10 Answers

5
B64b07d4b6cea9e5c3e1c272e6393a0d

(472)

on November 29, 2011
at 07:16 PM

Martin Berkhan recommends 14 hours for women and 16 hours for men as the ideal window. I personally do a daily 16 hour fast and find that to be perfect where I actually feel real hunger pangs but also don't want to throttle anyone in hunger-induced psychosis.

94a4a87e3d2e1e9160b6ed77678b4bea

(1311)

on November 29, 2011
at 09:56 PM

+1 for HANGRY - Love it!

Ba20b502cf02b5513ea8c4bb2740d8cb

(1669)

on December 02, 2011
at 04:46 AM

I'm the exact opposite; after the 16th hour I'm basically not thinking about food.

2
Dfada6fe4982ab3b7557172f20632da8

(5332)

on December 02, 2011
at 12:07 PM

Starting off by skipping a few meals is sensible. If you're already Paleo then you shouldn't have much to worry about with withdrawal, it's just a question of learning to understand the signals your body gives. I don't consider skipping a meal IF - I do it if I'm not hungry, and that's probably because I had a big meal in which case 8-10 of those 16 hours I was still digesting. I prefer occasionally going the whole day without food rather than having a routine, and find that to be most effective and easiest to stick to. But try different things and see what happens!

96bf58d8c6bd492dc5b8ae46203fe247

(37227)

on December 02, 2011
at 05:18 PM

I think the way to start is to have a nice large meal and then see how long it takes to get hungry. Over time, that interval may very well increase on its own.

2
Ba20b502cf02b5513ea8c4bb2740d8cb

on December 02, 2011
at 04:29 AM

For me, I experienced a noticable difference during the first day, espically if you train LISS (Low Intensity Steady State cardio @ about 65-75% of your MHR for 45 minutes +) in a fasted state.

I lowered body fat and for the following week after it seemed to have an effect on appetite suppression and cravings for dark chocolate (previous my first IF I craved dark chocolate every night).

Here's what my 24 hour fast proctocol (once a week):

9:00 PM

Fast started

7:30 AM

Wake Up

  • coffee
  • 1 scoop of SuperGreens drink
  • BCAA
  • 1000 mg fish oil

12:00 PM

  • coffee
  • 1 scoop of SuperGreens drink
  • BCAA
  • 1000 mg fish oil

3:00 PM

  • 1 scoop of SuperGreens drink
  • BCAA
  • 1000 mg fish oil

5:00 PM

  • 1 scoop of SuperGreens drink
  • BCAA
  • 1000 mg fish oil

7:00 PM

  • LISS (10K run @ a 8:30 min pace)

9:00 PM

  • Small Meal (Wild Caught Salmon, Arrugala, a little mayo); amlost zero carbs.

7:30 AM

  • Normal Paleo breakfast

Everybody is different; IF isn't recommended for anybody with eating disorders or people that are seriously obese or unhealthy(training during a fasted state can do kooky stuff to some). Basically for realitively fit people who are trying to fine tune their diet and give their stomach a break.

More good stuff:

NY Times Article on IF

PubMed Article on Beneifits

Medium avatar

(8239)

on December 03, 2011
at 04:56 AM

Thanks for being so specific about your regimen, SDD. I'm doing the Berkhan plan for a 3-month period. At the end I may revise in the direction of your protocol.

F44b15b2fd1ad134200793d6b474fc4c

(938)

on December 03, 2011
at 04:22 PM

Thanks for the detailed info, SSD.

Ba20b502cf02b5513ea8c4bb2740d8cb

(1669)

on December 02, 2011
at 11:54 PM

Yeah I could see that due to the fact that binge eaters are having some serious insulin highs and lows and IF might mititgae that a little...

96bf58d8c6bd492dc5b8ae46203fe247

(37227)

on December 02, 2011
at 05:17 PM

I have to disagree on not recommending IF for eating disorders and/or obese. I am a binge eater and started IF with at least 70 pounds still to lose. It's now 30-40 to lose, I'm losing the apple shape, and IF is the reason I'm succeeding. Others on PH have reported equally good results.

Ba20b502cf02b5513ea8c4bb2740d8cb

(1669)

on December 06, 2011
at 06:37 PM

Yeah I guess taking a gram of Fish Oil would be considered "breaking a fast" as well; I guess what you call what I'm doing is a decreased caloric intake for 24 hours supplementing with a greens drink. I don't fast for the sake of fasting or losing weight; Doing it for other reasons.

76c885d7d27e6c83542ea493ca866dcd

(2178)

on December 05, 2011
at 09:42 PM

I thought that ingesting anything but water broke a fast. doesn't having your SuperGreens drink break that up?

2
96bf58d8c6bd492dc5b8ae46203fe247

(37227)

on November 29, 2011
at 08:06 PM

First, you shouldn't do it at all if you don't want to. I found it a very natural thing.

It was natural because I like a large meal--it's important to eat until I feel full. When I do that, though, I don't feel hungry again for a long time.

So, there's no clock involved. I let my body tell me when to eat again. It could be the same day, but usually not. It could be the next morning, but frequently not. Most often, it's late morning to early afternoon the next day but if I'm busy it's no biggie to wait until night-time.

So do what feels right for YOU. If it's stressful to wait, go ahead and eat. You may IF all the time or only once in a while.

2
9f54852ea376e8e416356f547611e052

(2957)

on November 29, 2011
at 07:27 PM

I've been doing 16-18 hours off since February based on Martin's recommendations Erica also mentions (I'm a male). 7 days a week. Anything above 16 hours is pushing it for me hunger-wise, but I'm very tolerant to that. More than 16 hours also means your eating window is quite tight, and cramming all the calories might become a challenge on training days especially for those with poor appetite (me).

There's a period of a few days to two or so weeks when your body, hormones and metabolism gets used to IF, and I've heard some people have real problems adjusting.

There are many other ways to do IF, Dr Berardi did quite a bit of experimentation earlier this year on it, and wrote a very good introductory booklet to IF.

775bc83a7c54975e77a8500e065a24c3

(814)

on November 29, 2011
at 09:11 PM

Thanks for the link.

F44b15b2fd1ad134200793d6b474fc4c

(938)

on December 03, 2011
at 04:20 PM

Thanks so much for the info and for the link, Wisper.

1
32f5749fa6cf7adbeb0b0b031ba82b46

(41747)

on December 02, 2011
at 12:29 PM

The number I've seen range for 14 to 24 hours for benefits, with few deleterious effects up to 48 hours, all depending on what guru you listen to.

I used to IF once per week for 24 hours (usually after eating 3 squares a day over the weekend). I now do more or less a 8 hour feed window, simply by skipping breakfast (though my morning coffee is not completely calorie-free).

1
Ed983a42344945b1ff70fd9597a23493

on November 29, 2011
at 10:01 PM

I was doing two full days a week, and now have been doing a daily 8 hour or less eating window for over a month. I prefer the daily window, it works better for my life and my body. Experiment! Find what works for you...there are so many schools of thought on this, my m.o. is to see what my body likes through trial and error...

B4e1fa6a8cf43d2b69d97a99dfca262c

(10255)

on November 29, 2011
at 10:49 PM

2 day fasts once a week assisted in my initial weight loss when i was still SAD. the 2nd day was never pretty.

1
C59f469d51da372100083ff164e8f943

on November 29, 2011
at 08:52 PM

This is a great discussion. I tried IF for the first time on Sunday and skipped breakfast. I went about 18 hours. I felt weak, lightheaded and faint. I also did a hard workout (4 mile run/walk with sprinting intervals) and maybe I should have opted for more walking.

I can normally skip meals here and there and not feel the lighteadedness. Must be from the workout?

9f54852ea376e8e416356f547611e052

(2957)

on November 29, 2011
at 10:17 PM

It takes a while to get used to. I work out fasted, except for some BCAAs right before the workout. Heavy lifting, though, no cardio. The first time I did it wasn't too encouraging, now I have no issues.

96bf58d8c6bd492dc5b8ae46203fe247

(37227)

on December 02, 2011
at 05:15 PM

Working out fasted is a good test to see if you've fully adapted to releasing/burning stored fat. Better luck on your next try!

1
77877f762c40637911396daa19b53094

(78467)

on November 29, 2011
at 08:25 PM

I feel way too lemming-ish to say this, but 16-18 hrs works great for me, almost every day. It seemed a pipe dream on Paleo Day #1 to be able to do this. But it happened within two weeks.

1
C56baa1b4f39839c018180bf63226f7d

on November 29, 2011
at 08:18 PM

I try to make my IF window be at least 18 hours, but I don't feel the need to IF every day (since as mentioned elsewhere in the thread, a fasting window this long every day makes for a short refeeding window). I set it up so that MWF I have dinner but no lunch, and that usually nets me about 20-22 hours (less if I'm out having a drink the previous night). It took me a few months to really get used to it; I started in March this year, and later in the spring I was rather devoid of energy, but I adjusted and have had no problems since.

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