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Although I haven't attempted this myself, I have seen many people attempt to endure a 72 hours fast (as part of diagnosing a potential pheochromocytoma) and the

Although I haven't attempted this myself, I have seen many people attempt to endure a 72 hours fast (as part of diagnosing a potential pheochromocytoma) and the majority experience this as extremely difficult. I wonder if multiple shorter fasts — e.g., a 24 hours fast once a week — could be as beneficial.

snowpanda 10y ago
I have fasted for approximately a week on 4 different occasions and interestingly enough the 72 hours that you mentioned are indeed the hardest. For me personally it started getting easier at that specific 72 hour mark. In regards to the multiple 24 hours fast I was wondering the same thing reading this article. Although I think it might not work because of the white blood cells regenerating.
- StavrosK 10y ago
  I don't think that's fasting any more, sounds more like starvation, to me.
  - hyperdunc 10y ago
    No, hunger disappears around day 3, then returns with a vengeance shortly before death, which can be up to 3 months later. This second burst of hunger is actual starvation.
dazzawazza 10y ago
I regularly fast for 20+ hours (calorie restriction, I do drink water because I am not an idiot) once or twice a week. You get very used to it. While its not something I look forward to, it's purely psychological. A few hours after I miss 'breakfast' my tummy rumbles two or three times and then my body doesn't care anymore. The max time I've fasted is forty hours and I have to say if you can get past the first fours hours, it's easy. I didn't really plan to fast that long, circumstances led to it. I actually found it hard to eat after it. I normally eat a very small 500-600 calorie meal after a fast but I couldn't finish it after the long fast. I think we underestimate how adaptable our body is and how intermittent fasting is actually the norm for most mammals.
- mattmanser 10y ago
  How is a 500-600 calorie meal 'very small'? Most normal dinners are 600-800 calories.
  - tbihl 10y ago
    If you're used to 800, 500 is a pretty huge drop. My intake to maintain weight is about 2600kcal/day as a lightly-moderately active person. I normally do a breakfast of about 400-500 calories, and then 900-1000 for lunch and dinner. So if I weren't just waking up, 500-600 would be very small for me.
  - collyw 10y ago
    Rat studies have shown that 30% of the normal calorie intake can have similar benefits to "proper" fasting.
  - dazzawazza 10y ago
    Sorry, the small refers to the physical volume of the meal.
- ashark 10y ago
  I tried single day (don't eat anything in a single waking period, not strict 24-hours—over 24 hours, in fact) fasting a few times a couple years back. I don't usually eat breakfast anyway (rarely feel hungry in the morning), but ~1hr after I usually eat lunch I'd feel fairly bad, and by 3pm or so I'd feel quite weak and mentally sluggish. I still plan to try a 72 hour fast at some point, but I'm expecting it to be very unpleasant based on those experiences.
baccheion 10y ago
If you're going to do shorter fasts, you may as well just eat within the same 8-hour window each day. That approach can be even more beneficial than skipping meals for one day each week. After doing this for a while (and ensuring you don't have any nutrient deficiencies), a water fast shouldn't be that difficult. If it is, then you can transition into it with a juice fast.
gtirloni 10y ago
I don't like doing shorter fasts because you only experience the worst part of them. The first 3-4 days are the worst and then everything clears (pre-existing conditions in skin/joints/intestine, mind fogginess, etc). Going out of the fast is a good time to experiment with food/situations and see what could be causing some of the issues you've been experiencing (if any). I usually go for a 7-day water fast twice a year (and just completed one a few weeks ago). The results are obvious to me. YMMV. Mandatory warning: I'm not a doctor and this is not medical advice. Talk to your doctor.

snowpanda 10y ago

I have fasted for approximately a week on 4 different occasions and interestingly enough the 72 hours that you mentioned are indeed the hardest. For me personally it started getting easier at that specific 72 hour mark. In regards to the multiple 24 hours fast I was wondering the same thing reading this article. Although I think it might not work because of the white blood cells regenerating.

StavrosK 10y ago
I don't think that's fasting any more, sounds more like starvation, to me.
- hyperdunc 10y ago
  No, hunger disappears around day 3, then returns with a vengeance shortly before death, which can be up to 3 months later. This second burst of hunger is actual starvation.

dazzawazza 10y ago

I regularly fast for 20+ hours (calorie restriction, I do drink water because I am not an idiot) once or twice a week. You get very used to it. While its not something I look forward to, it's purely psychological. A few hours after I miss 'breakfast' my tummy rumbles two or three times and then my body doesn't care anymore. The max time I've fasted is forty hours and I have to say if you can get past the first fours hours, it's easy. I didn't really plan to fast that long, circumstances led to it. I actually found it hard to eat after it. I normally eat a very small 500-600 calorie meal after a fast but I couldn't finish it after the long fast. I think we underestimate how adaptable our body is and how intermittent fasting is actually the norm for most mammals.

mattmanser 10y ago
How is a 500-600 calorie meal 'very small'? Most normal dinners are 600-800 calories.
- tbihl 10y ago
  If you're used to 800, 500 is a pretty huge drop. My intake to maintain weight is about 2600kcal/day as a lightly-moderately active person. I normally do a breakfast of about 400-500 calories, and then 900-1000 for lunch and dinner. So if I weren't just waking up, 500-600 would be very small for me.
- collyw 10y ago
  Rat studies have shown that 30% of the normal calorie intake can have similar benefits to "proper" fasting.
- dazzawazza 10y ago
  Sorry, the small refers to the physical volume of the meal.
ashark 10y ago
I tried single day (don't eat anything in a single waking period, not strict 24-hours—over 24 hours, in fact) fasting a few times a couple years back. I don't usually eat breakfast anyway (rarely feel hungry in the morning), but ~1hr after I usually eat lunch I'd feel fairly bad, and by 3pm or so I'd feel quite weak and mentally sluggish. I still plan to try a 72 hour fast at some point, but I'm expecting it to be very unpleasant based on those experiences.

baccheion 10y ago

If you're going to do shorter fasts, you may as well just eat within the same 8-hour window each day. That approach can be even more beneficial than skipping meals for one day each week. After doing this for a while (and ensuring you don't have any nutrient deficiencies), a water fast shouldn't be that difficult. If it is, then you can transition into it with a juice fast.

gtirloni 10y ago

I don't like doing shorter fasts because you only experience the worst part of them. The first 3-4 days are the worst and then everything clears (pre-existing conditions in skin/joints/intestine, mind fogginess, etc). Going out of the fast is a good time to experiment with food/situations and see what could be causing some of the issues you've been experiencing (if any). I usually go for a 7-day water fast twice a year (and just completed one a few weeks ago). The results are obvious to me. YMMV. Mandatory warning: I'm not a doctor and this is not medical advice. Talk to your doctor.