I have read about and tried intermittent fasting in the past few months with some great results. The only hiccup was getting sick for about 3 weeks and losing that will to continue with it, until I restarted it recently. I was wondering what others experience were with intermittent fasting and also any recommendation of websites, books, research, etc on the subject. My personal experience is that when I am fasting I actually feel better and seem to be a bit more engergized. I even feel more energy when I workout in a fasted state.


2 Answers 2



This is the site of Martin Berkhan, who is a guy who has based his entire coaching on the concept of intermittent fasting. He is a Swede, but the site is in English. It's quite a large repository of info, and it includes a bunch of before / after testimonies from some of his clients.

Personally, I've had very good results with the Leangains approach of a 16hr fast each day, combined with a paleo diet. I've dropped at least one pant size in the first 2 - 3 weeks. I don't know how much of that is due to the paleo or the IF. I try to do some walking or short, intense exercise while fasted (it wouldn't be a good idea to do a metabolic conditioning type of training as those require a lot of glucose and you could end up in glucose deficit.)

Alternatively, Tim Ferriss advocates a protein fast once a week, to trigger autophagy and other cell renewal mechanisms.

  • 3
    Why the -1 vote? I.F. might or not be a good idea, but my answer is an adequate response to the question asked.
    – JDelage
    Mar 9, 2011 at 11:41
  • 2
    This is a bad response, because "It may not be a good idea" Mar 9, 2011 at 15:35
  • 2
    Hmm. A paleo diet may be a bad idea? Or intermittent fasting may be a bad idea? Pretty vague comments. I'd be curious if there is actual science behind the claim that "this isn't generally good advice." +1 to get you out of the hole
    – J. Win.
    Mar 11, 2011 at 7:02
  • 4
    If fasting 8-12 hours at night is normal for pretty much everybody on the planet, how does 16 hours of it cause "undue stress?" Doing 50 pushups, sprinting up the stairs or running 10k also cause stress, but we recognize these stresses stimulate our bodies to grow stronger. Aside from that, the question asked for references about intermittent fasting, and a legitimate answer got downvoted with no explanation because somebody thinks intermittent fasting is a bad idea? That's not what I want this site to become. What's next, downvoting answers about vegetables because I don't like them?
    – J. Win.
    Mar 16, 2011 at 23:20
  • 2
    Grazing is good for food companies. So remember: eat 10 times a day or you will get fat and ugly!
    – gruszczy
    Nov 29, 2011 at 10:52

Fasting for an extended period of time (usually more than 3 days) places your body into a state of ketosis, and you begin burning any excess fat on your body. If you are overweight and have fat that you can safely lose (safe is relative, but definitely over 3% body fat), then fasting will not hurt you as long as you get plenty of liquids. (see my answer to "At what point do I start to burn muscle on a calorie deficit diet?"

That being said, if you fast for 3 days and then eat like a pig for 3 days, you're going to do yourself some serious harm. There are no known benefits to intermittent fasting exceeding the benefits of simple calorie reduction. If you're looking to lose weight, restrict your calories first.

Personally, I'm a big fan of the Atkins diet. It places your body into the same state of ketosis as fasting, but you still get to eat as well. Even with Atkins though, you will still gain or maintain your weight if you eat too many calories. Atkins is safe while you are sick under most circumstances. Fasting can be seriously detrimental while you are sick if not done properly.

  • 4
    "if you fast for 3 days and then eat like a pig for 3 days, you're going to do yourself some serious harm" Do you have evidence for this? Since I.F. eaters dont necessarily eat fewer calories overall, there has to be some heavy eating going on during the non-fasting periods.
    – J. Win.
    Mar 11, 2011 at 7:00
  • 1
    You don't need to fast for three days to be in ketosis. In fact, you don't need to fast at all to be in ketosis. Ketosis means that your body is using fat rather than ingested glucose. It enters this stage if you don't ingest enough gucose. So any sufficiently low carb diet will eventually induce ketosis - even if you're eating plenty of proteins and fats.
    – JDelage
    Mar 11, 2011 at 8:51
  • @JDelage - I understand that, however, most people ingest enough carbs that it takes about three days for their bodies to flush them all out. Mar 11, 2011 at 13:42
  • @J. Winchester - Overeating (once) sends excess blood to your digestive tract to successfully carry away and store all the calories, vitamins, and nutrients that you've consumed. Just the first time you overeat, your triglyceride levels begin to climb. All of this increases the levels of stress on your body, and it's the same reason you shouldn't take all your vitamins at once if you can do otherwise. Mar 11, 2011 at 13:56

Not the answer you're looking for? Browse other questions tagged or ask your own question.