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Do you eat more calories following IFing

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  • Do you eat more calories following IFing

    For those who fast for periods of 24 hours or more... do you eat more calories the days following the fast? I fasted from Sunday night to Tuesday morning. I ate light on Tuesday and Wednesday (probably 1500 calories each day). And now i think its catching up to me. I don't feel hungry, just very tired. Too tired to workout. Has anyone expierenced this?

  • #2
    I do... but I'm currently deployed and don't eat a whole lot to begin with (food selection is um... sub-par).


    • #3
      It depends on a lot...

      For example:

      *IF* you are on very low carbs, and you are at a very low activity level, you will likely not see the symptoms you are expressing. Your body will likely be in ketosis. This means that your brain will be using ketones for energy. The glycogen stores of your liver will be low, but the ketones will make up for that. And, with a low activity level, you shouldn't see that much glycogen depletion in your muscels.

      On the other hand, if you are on moderate carbs, and/or higher activity levels, your recovery from the fast will be different.

      During the fast, you probably reduced the glycogen stores of your liver, and your body may not have switched over to ketone production for brain activity. This leads to lethargy. Any work outs that you may do will have reduced the glycogen stores of your muscels. This leads to poor muscle responses.

      If this is what is happening, it is not so much how much you eat, as much as what you eat.

      If your tired feeling is coming from reduced glycogen in your liver and/or muscels, you need to eat stuff to top off these stores again. (Or, continue with low carb, and go into ketosis).

      This would mean eating good, complex carbs, and starchy vegitables: Sweet potaoes, carrots, rice.

      Fruit could also help, but, be aware that fruit contains both fructose and glucouse. The fructose in the fruit is synthesized into glycogen that can only be bound for the liver. If the liver stores are full, it will go to fat. The glucose, when synthesized can be used by either the liver or the muscels.

      Your complex carbs, on the other hand are all glucose. So, the carbs you eat can go to the liver, or, when that is full, the muscels. It would only be when the liver AND the muscels are full that the glucose in the carbs get stored as fat.


      • #4
        No, I don't.
        My Fitday public journal.
        Me vs. Russian Boar, hunt is on Aug. 20th. WHAT'S MORE PRIMAL THAN THAT?!
        Recently survived Warrior Dash, New England.
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        • #5
          Originally posted by Primal Bill View Post
          just very tired. Too tired to workout. Has anyone expierenced this?
          It sounds like you shouldn't fast that long and you might get more energy for your workouts if you eat a bit more cals.

          I usually eat a regular size meal after a 24hr fast and I have lots of energy.

          What are your current fitness/body composition goals right now?


          • #6
            Waskydiver - Thanks for the detailed reply.

            To give you some background info about myself. I started eating according to the PB 8 weeks ago. I'm 5'7. I was 167 and am now down to 156. I'm in decent shape, but i've been following CW (eating high carb diet) for so long that i've stored a lot of belly fat that i'm trying to get rid of. Since i've started i've been eating on average 100 gs of carbs a day, about 120 gs of protein, and the rest fat (to give me about 2000 calories a day). I feel great, and could skip a meal here or there and still feel great. So this past monday i fasted for the whole day. Monday i did cardio for about 30 mins, and tuesday some squats. Wednesday I did not workout, and today i started feeling very very tired in the afternoon. I think the lack of calories for the week is catching up to me. My overall goal is to get to single digit body fat (or at least have a six pack) while maintaining muscle.


            • #7
              Bill, you're already at a low amount of calories so eat up for a few days.


              • #8
                I know i should probably be eating at least 2000, and closer to 2200 calories. But i'm trying to accelerate the fat loss. I've been following a very strict pb diet (low carbs from vegetables, quality protiens and fats), so i'm hoping my body has adapted to burning stored fat to make up for the low calories


                • #9

                  I've been doing a Leangains-style IF for about a month now, maybe 5 weeks? I have a 'feed' period for 8 hours, from about 1 p.m. until about 9 p.m. I'm still moving to a fully-primal diet, but was already eating few carbs, almost no sugar, no HFCS, and no packaged/processed foods, so as it stands I'm *farily* primal.

                  Within about a week and a half of starting IF, I had dropped from about 159lbs to about 151lbs, and I suspect that's mostly fat (plus water as my body has adjusted). I haven't been tracking calories, really, and, in fact, I think I'm eating the same or MORE than I was eating before IF. I say that because I used to have a protein shake for breakfast, and now I have that, along WITH a salad, for lunch @ 1 p.m. I snack as-needed during the afternoon - carrots, an apple, maybe a piece of cheese, and nuts. (this is the same as I did pre-IF). Dinner, I eat a fairly primal meal: some kind of animal protein, a large serving of veg, often berries with a splash of heavy cream for dessert.

                  All this to say: I believe, at least in my case, that 18 daily hours of fasting has helped increase my insulin sensitivity, has mobilized some stored fat, and has left me feeling pretty good. I work out fasted, in the morning, and per Leangains, have 10g BCAA both before and after my workout. I also have a cup or two of coffee, again with a tiny splash of cream or half-and-half. I found that once I settled into this routine, my energy throughout the day has mostly been really good and strong. The *only* time I feel a lag, if ever, is the hour or 90 minutes right before my fast break. This is a good 4 hours after my workout, so it's not affecting that. If I feel really hungry, I just go ahead and break my fast early. If it's not bad, I usually just wait until 1.

                  I'm not sure if this really answers your question, but I guess my point is: perhaps trying a different IF protocol would help you with your energy ups and downs?
                  “If you want to build a ship, don't drum up people together to collect wood and don't assign them tasks and work, but rather teach them to long for the endless immensity of the sea” -- Antoine de Saint-Exupery


                  • #10
                    I do the IFing fairly often, so I do an 18 hour fast. My eating-window is 8 hours, from breakfast at 7.30 and then lunch at 1.30 pm. I don't feel hungry enough to snack or eat dinner. I feel very energetic and it hasn't affected my exercise. I don't think I could fast for more than 18 hours though!


                    • #11
                      Originally posted by Primal Bill View Post
                      Since i've started i've been eating on average 100 gs of carbs a day
                      That's the key...

                      100 grams of carbs is most likely not enough to put you into ketosis.

                      You did cardio, squats, and an IF. This knocked down your glycogen stores.

                      When you broke your fast, your body wanted to replenish your glycogen stores, so it turned down the volume on your energy, diverting the carbs you were eating to your glycogen stores.

                      At the same time, your body was probably attempting to make the transition into ketosis to provide your brain with energy in the absense of liver glycogen.

                      I would fully expect you to be feeling like carp during this time.

                      If you are going to maintain "moderate" carbs (75ish to about 150ish), and you are going to maintain your activity level, and do IF's, you are going to want to break your fasts with some carbs to get your liver glycogen back to where it's comfortable.

                      Or, MAINTAIN a lower level of carbs (less than 50). This should keep you in a state of ketosis. The ketones will act as a buffer for your liver glycogen. If it gets too low, or is refilling, your ketones will be there to provide your brain energy.

                      Ketones, though are not the cure all, though. You let your liver and muscel glycogen stores get low enough (think chronic cardio), your body is going to want to get a baseline glycogen back, so you can expect lethargy even while in ketosis under these conditions.

                      FYI: I am personally struggling with trying to fine tune this myself. I have been in a state of very low carbs (usually less than 30 grams a day), and have been in ketosis for 5 or 6 months now. I have recently greatly increased my activity level (running about 15 miles per week), and am looking towards a longer term goal of a marathon.

                      Over the last 5 months, I have been feeling TERRIFIC while in ketosis. Going through 24 hour IF's has been a piece of cake. But with adding this extra activity, I have to be really careful of how I manage my fuel. If I do not get enough of the right kind of food, I might feel great during a five mile run... But the next day, I will feel like I haven't slept for a week.

                      On, the other hand, too many carbs, and I risk knocking myself out of ketosis, and denying my body the extra fat burning fuel potential for my longer runs that comes with it.


                      • #12
                        I eat one huge meal in the evenings and then fast ~22 hours til the next. It takes me 1-2 hours to finish eating so I guess that's my "eating window." I just have a voracious appetite and have no problem demolishing a few plates of food in one sitting. Because of this, my calorie intake stays fairly constant because I'll reach a limit on how much I can stuff down my gullet. Usually 2000-2400 calories depending on my activity level that day and what I'm feasting on.


                        • #13
                          I have started fast-5 and while it's not more then 24 hours I haven't eaten more. Those times I have done some 23 hour fasts I did not eat more either. So far my energy has been terrible lately and I think it's from trying to eat more carbs. I don't think ~100 works for me at all.
                          Female, 5'3", 50, Max squat: 202.5lbs. Max deadlift: 225 x 3.