1

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Activity Levels During Intermittent Fasting

Answered on August 19, 2014
Created July 18, 2012 at 3:40 PM

I read on a post recently where someone was suggesting to rest or don't do physical activity during IF. My personal take is I feel just fine doing any level of activity. I regularly do long hikes the day of an IF, having eaten the night before and eat the evening I get back. My only precaution is heavy strenght training, which I would only do at the end of an IF, right before eating.

I am curious as to other people's thoughts on this subject. Do you rest during IF? Do you have the same energy level? Etc. Or does it depend on the duration. For example I consider IF at least 16-18 hrs, and really not until closer to 24 hrs.

9bd33dab06ad6696b1b6a06aed818f05

(659)

on July 19, 2012
at 01:43 AM

nice analogy with the vest, i like.

C45d7e96acd83d3a6f58193dbc140e86

on July 19, 2012
at 12:12 AM

Look up the definition of intermittent. What you are doing is a specific feeding window everyday. IF is more trying to recreate the idea that paleolithic man did not always have 3 squares. Sometimes yes, sometimes no.

F5be4be097edc85690c12d67ee1a27c0

(1884)

on July 18, 2012
at 07:38 PM

No, I think by definition that's exactly intermittent fasting... "Intermittent fasting (IF) is a pattern of eating that alternates between periods of fasting (usually meaning consumption of water only) and non-fasting." I don't think a pattern is necessarily sporadic.

C45d7e96acd83d3a6f58193dbc140e86

on July 18, 2012
at 07:14 PM

By definition, that is not intermittent fasting. Intermittent-occurring at irregular intervals, sporadic. We are talking about completely different things. I am familiar with Leangains. I know it is somewhat popular on here, mainly because the guy is a good marketer.

C45d7e96acd83d3a6f58193dbc140e86

on July 18, 2012
at 07:11 PM

Agreed about following intense activity with nutrition.

F5be4be097edc85690c12d67ee1a27c0

(1884)

on July 18, 2012
at 06:40 PM

Well the 8 hr eating/16 hour fasting is the Leangains programming. I just checked out his website just to be sure, and he said he's done it every day since 2005/2006 or something.

Dfe1dfb34939145fe21b3d8fa6832365

(657)

on July 18, 2012
at 06:21 PM

My experience too. Low mid level activity is fine, but the really taxing stuff should be followed by a decent amount of nutrients.

C45d7e96acd83d3a6f58193dbc140e86

on July 18, 2012
at 06:19 PM

I like your comparison to a weight vest, especially with regards to carbs before a race. Rather than a necessity, I look at carbs as an extra boost of energy.

C45d7e96acd83d3a6f58193dbc140e86

on July 18, 2012
at 06:17 PM

We shall agree to disagree. Can I ask why you think it should be everyday?

F5be4be097edc85690c12d67ee1a27c0

(1884)

on July 18, 2012
at 06:05 PM

Well actually I believe IF should be an everyday thing that you do for forever, like eating paleo. Two weeks is very little and probably wasn't enough for him to adjust to properly or figure out a way to supplement his workouts.

C45d7e96acd83d3a6f58193dbc140e86

on July 18, 2012
at 05:20 PM

I have 5% BF, but not adrenal issues. For anyone doing HIIT, agreed that you shouldn't prolong eating that long after a workout, mainly because of muscle recovery. I can do HIIT but it must be near the end of my IF. If I do it in the morning, but don't eat until much later, I will be sore the next day.

C45d7e96acd83d3a6f58193dbc140e86

on July 18, 2012
at 04:24 PM

Two weeks of IF is quite a lot, and will definitely cause a reduced strength and energy level for most people.

F5be4be097edc85690c12d67ee1a27c0

(1884)

on July 18, 2012
at 04:03 PM

^ I assume if you can forcefeed yourself and have a healthy appetite, you may not run into this problem whatsoever.

F5be4be097edc85690c12d67ee1a27c0

(1884)

on July 18, 2012
at 04:03 PM

He did it for two weeks and for our past two weight lifting sessions he got REALLY pissed about his weights decreasing and not having enough energy. He did 8 hr eating/16 hr fasting five days out of the week. He DID lose weight (3-4 lbs), but I don't think bad workouts are worth it to him. He also found it difficult to forcefeed himself when he developed a small appetite from IF itself.

C45d7e96acd83d3a6f58193dbc140e86

on July 18, 2012
at 03:56 PM

How often was he doing it? I aim for a 24 hr IF once every 7-10 days. But I regularly only eat twice a day, and never more than 3 times. So maybe I am more adjusted.

C45d7e96acd83d3a6f58193dbc140e86

on July 18, 2012
at 03:55 PM

I like the hunter-gatherer reference to having to hunt or search for food.

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4 Answers

4
7fb6efb15030ea965d00be6e8eb13fd4

(253)

on July 18, 2012
at 03:50 PM

I do intermittent fasting and and I'm also a high school athlete. I find that exercising while fasting makes me more alert and quick on my feet. Most days, I have a good hard strength workout right before 12-1pm and then break the fast by eating a big meal. (Eggs with some ground beef and ghee is my all time fave.) Paleolithic hunter gatherers often had to hunt or search for food on an empty stomach so I figure exercising a little while intermittent fasting is just fine. Just be sure to eat a big meal when you're done working out so you muscles can recover & rebuild.

C45d7e96acd83d3a6f58193dbc140e86

on July 18, 2012
at 03:55 PM

I like the hunter-gatherer reference to having to hunt or search for food.

2
3ce6a0d24be025e2f2af534545bdd1d7

(26217)

on July 18, 2012
at 05:29 PM

I have two types of IF I go through: Natural and Planned. With Natural IF I just don't eat if I'm not hungry. Probably 3-4 days a week I won't eat breakfast because I am simply not hungry. With planned IF I plan ahead that after dinner on day 1 (usually 630-7) I won't eat again until the following dinner. I never do planned IF on days that I lift heavy.

In terms of activity levels, I maintain the same activities. I've seen that my longer runs and temp runs are more difficult on days that I IF, but that hasn't stopped me. I think of it like having a weight vest on -- I am purposely putting a load on my system so that it becomes better at burning fat for fuel. Then when I take the vest off (i.e. put some carbs in my system before a race) I feel much faster.

C45d7e96acd83d3a6f58193dbc140e86

on July 18, 2012
at 06:19 PM

I like your comparison to a weight vest, especially with regards to carbs before a race. Rather than a necessity, I look at carbs as an extra boost of energy.

9bd33dab06ad6696b1b6a06aed818f05

(659)

on July 19, 2012
at 01:43 AM

nice analogy with the vest, i like.

0
Dfe1dfb34939145fe21b3d8fa6832365

on July 18, 2012
at 05:01 PM

If you have extremely low body fat naturally like I do, coupled with possible adrenal issues, be careful of water fasting and exercising hard during the fasted period. I've just about killed myself doing HIIT in the morning then trying to fast the rest of the day.

Dfe1dfb34939145fe21b3d8fa6832365

(657)

on July 18, 2012
at 06:21 PM

My experience too. Low mid level activity is fine, but the really taxing stuff should be followed by a decent amount of nutrients.

C45d7e96acd83d3a6f58193dbc140e86

on July 18, 2012
at 07:11 PM

Agreed about following intense activity with nutrition.

C45d7e96acd83d3a6f58193dbc140e86

on July 18, 2012
at 05:20 PM

I have 5% BF, but not adrenal issues. For anyone doing HIIT, agreed that you shouldn't prolong eating that long after a workout, mainly because of muscle recovery. I can do HIIT but it must be near the end of my IF. If I do it in the morning, but don't eat until much later, I will be sore the next day.

0
F5be4be097edc85690c12d67ee1a27c0

on July 18, 2012
at 03:53 PM

My boyfriend was doing IF, and it really started screwing up his strength... it also screwed up his appetite to fuel workouts. I think he backed off of doing IF for a while.

F5be4be097edc85690c12d67ee1a27c0

(1884)

on July 18, 2012
at 06:05 PM

Well actually I believe IF should be an everyday thing that you do for forever, like eating paleo. Two weeks is very little and probably wasn't enough for him to adjust to properly or figure out a way to supplement his workouts.

F5be4be097edc85690c12d67ee1a27c0

(1884)

on July 18, 2012
at 07:38 PM

No, I think by definition that's exactly intermittent fasting... "Intermittent fasting (IF) is a pattern of eating that alternates between periods of fasting (usually meaning consumption of water only) and non-fasting." I don't think a pattern is necessarily sporadic.

C45d7e96acd83d3a6f58193dbc140e86

on July 18, 2012
at 07:14 PM

By definition, that is not intermittent fasting. Intermittent-occurring at irregular intervals, sporadic. We are talking about completely different things. I am familiar with Leangains. I know it is somewhat popular on here, mainly because the guy is a good marketer.

C45d7e96acd83d3a6f58193dbc140e86

on July 18, 2012
at 06:17 PM

We shall agree to disagree. Can I ask why you think it should be everyday?

C45d7e96acd83d3a6f58193dbc140e86

on July 19, 2012
at 12:12 AM

Look up the definition of intermittent. What you are doing is a specific feeding window everyday. IF is more trying to recreate the idea that paleolithic man did not always have 3 squares. Sometimes yes, sometimes no.

F5be4be097edc85690c12d67ee1a27c0

(1884)

on July 18, 2012
at 04:03 PM

He did it for two weeks and for our past two weight lifting sessions he got REALLY pissed about his weights decreasing and not having enough energy. He did 8 hr eating/16 hr fasting five days out of the week. He DID lose weight (3-4 lbs), but I don't think bad workouts are worth it to him. He also found it difficult to forcefeed himself when he developed a small appetite from IF itself.

F5be4be097edc85690c12d67ee1a27c0

(1884)

on July 18, 2012
at 04:03 PM

^ I assume if you can forcefeed yourself and have a healthy appetite, you may not run into this problem whatsoever.

C45d7e96acd83d3a6f58193dbc140e86

on July 18, 2012
at 04:24 PM

Two weeks of IF is quite a lot, and will definitely cause a reduced strength and energy level for most people.

C45d7e96acd83d3a6f58193dbc140e86

on July 18, 2012
at 03:56 PM

How often was he doing it? I aim for a 24 hr IF once every 7-10 days. But I regularly only eat twice a day, and never more than 3 times. So maybe I am more adjusted.

F5be4be097edc85690c12d67ee1a27c0

(1884)

on July 18, 2012
at 06:40 PM

Well the 8 hr eating/16 hour fasting is the Leangains programming. I just checked out his website just to be sure, and he said he's done it every day since 2005/2006 or something.

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