2

votes

How bad are the effects of fasting for 72 hours?

Answered on September 12, 2014
Created June 13, 2011 at 4:01 AM

Hi!

I've been on IF + Paleo to lose weight for three weeks. The results are not bad: 11 of my 50 extra pounds were lost in two weeks, however I've not lost a single pound in this third week, so I'm considering adding a second fasting day to my regimen, instead of stressing myself with portion sizes.

How bad are the effects of doing so, ie, of turning a 48-hour period of fasting intto a 72-hour period? I'm going to lose some muscle mass, but isn't it negligible?

As for the exercise I'm currently doing, besides walking a reasonable amount (6-12km everyday), I do some weight lifting for a very short time, like 5-10min.

Thanks!

667f6c030b0245d71d8ef50c72b097dc

(15976)

on September 07, 2013
at 01:28 AM

I too would hesitate before going that long. Our bodies can handle the occasional 24 hour period but there's not much research indicating that we are suited to fasting longer than that. Even if one is completely adapted to burning fat, and not suffering from blood sugar issues, they are going to have serious hunger pangs after that long. Which I would say is going to interfere with normal functioning throughout the day. I'd think one would become too focused on food food food after that long.

E35e3d76547b18096a59c90029e7e107

(15613)

on September 07, 2013
at 01:28 AM

And also although 50g is reassuringly little for a couple of days of fasting, they'd still have lost 1.5kg/~3.3lbs of muscle after 30, which is plenty!

1a98a40ba8ffdc5aa28d1324d01c6c9f

(20378)

on June 15, 2011
at 02:59 AM

Too Funny. It is sort of like: http://robbwolf.com/faq/ Look for fat loss. Indeed pretty standard eating. Maybe palm and fingers :-)

667f6c030b0245d71d8ef50c72b097dc

(15976)

on June 14, 2011
at 12:51 PM

umm, how is this not just normal eating? Does anyone on these boards ever have a meal that does NOT have a large piece of protein. (btw, size of your palm? huhwut?! I think i need bigger palms)

E35e3d76547b18096a59c90029e7e107

(15613)

on June 14, 2011
at 07:49 AM

Thanks guys! @ Ben. The person seems to be burning ~2250cal per day throughout, so between the average man and the average woman. I agree that we'd want to know the details, given Peter/Hyperlipid's recent thing about the obese losing *less* weight than the lean while fasting. I agree that they'd need to degrade more muscle once they ran out of fat. Whoever they were, they seem to have lost fat/muscle in very consistent amounts. Over those 30 days they lost ~6kg of fat, but even at my weight (70kg), 15% bodyfat would still give 10.5kg of fat stores...

77877f762c40637911396daa19b53094

(78467)

on June 13, 2011
at 02:50 PM

This just rocks!!! Thanks for sharing his blog with us.

667f6c030b0245d71d8ef50c72b097dc

(15976)

on June 13, 2011
at 02:24 PM

I'd agree. Mirror and camera with the same lighting is much more effective than using only a scale. I do weigh myself and I'll admit that I start tinkering if I see too much weight gain too quickly but a mirror is more useful, especially if you are doing activity that is actually building muscle.

667f6c030b0245d71d8ef50c72b097dc

(15976)

on June 13, 2011
at 02:23 PM

Oh and you got my first up vote:) going to try and start voting for good answers more. Cheers.

667f6c030b0245d71d8ef50c72b097dc

(15976)

on June 13, 2011
at 02:22 PM

Excellent graph and excellent answer. I would hasten to add that there is nothing stated about the individual. He or she, fat skinny, age, weight, BMI, activity level etc. Difficult to extrapolate. I think that if a very active, fit, muscled individual with say 10-15% bodyfat were to fast this long we may see more muscle degradation, ie protein-loss.

7e746be2f0e550a8cd7df881322ae705

(18701)

on June 13, 2011
at 11:51 AM

Nicely done, David! And with pictures!

Fc7712b6a931b618ffaf4d6475b5d8f4

(200)

on June 13, 2011
at 07:37 AM

Lots of water and tea!

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6 Answers

best answer

11
E35e3d76547b18096a59c90029e7e107

(15613)

on June 13, 2011
at 05:38 AM

Some of the most useful posts on fasting I've seen are these at the Health Correlator blog.

Most useful of all is the following chart:

how-bad-are-the-effects-of-fasting-for-72-hours?

This has greatly reassured me about fasting (and calorie restriction in general) in that even after extended, complete fasting, the subjects only lost around 50g of protein per day. This is reassuringly little, as it always seemed to me (and sensible outside observers) that I absolutely haemmoraged muscle if I didn't get enough protein and/or restricted calories.

The other thing that bears noting is that you're only going to lose around 200=250g (=1800-2250 calories) of fat per day and that the first 3 days, where you're losing up to 1.75kg of mass per day are mostly water and carbohydrate. I think this is particularly important to note, given that so many people frustratedly observe that they lost a huge amount of weight at the beginning of paleo and now they've 'stalled' and wondering whether this means that paleo doesn't work or that they need to radically change their diet. In fact, you can only expect a certain limited amount of weight loss, after the quick loss of water and carbohydrate, even if totally fasting.

7e746be2f0e550a8cd7df881322ae705

(18701)

on June 13, 2011
at 11:51 AM

Nicely done, David! And with pictures!

77877f762c40637911396daa19b53094

(78467)

on June 13, 2011
at 02:50 PM

This just rocks!!! Thanks for sharing his blog with us.

E35e3d76547b18096a59c90029e7e107

(15613)

on September 07, 2013
at 01:28 AM

And also although 50g is reassuringly little for a couple of days of fasting, they'd still have lost 1.5kg/~3.3lbs of muscle after 30, which is plenty!

667f6c030b0245d71d8ef50c72b097dc

(15976)

on June 13, 2011
at 02:23 PM

Oh and you got my first up vote:) going to try and start voting for good answers more. Cheers.

E35e3d76547b18096a59c90029e7e107

(15613)

on June 14, 2011
at 07:49 AM

Thanks guys! @ Ben. The person seems to be burning ~2250cal per day throughout, so between the average man and the average woman. I agree that we'd want to know the details, given Peter/Hyperlipid's recent thing about the obese losing *less* weight than the lean while fasting. I agree that they'd need to degrade more muscle once they ran out of fat. Whoever they were, they seem to have lost fat/muscle in very consistent amounts. Over those 30 days they lost ~6kg of fat, but even at my weight (70kg), 15% bodyfat would still give 10.5kg of fat stores...

667f6c030b0245d71d8ef50c72b097dc

(15976)

on June 13, 2011
at 02:22 PM

Excellent graph and excellent answer. I would hasten to add that there is nothing stated about the individual. He or she, fat skinny, age, weight, BMI, activity level etc. Difficult to extrapolate. I think that if a very active, fit, muscled individual with say 10-15% bodyfat were to fast this long we may see more muscle degradation, ie protein-loss.

4
6b8d12fc3e43179f9ae1765a4d1a9dc2

(5914)

on June 13, 2011
at 05:41 AM

Konrad, you are not going to lose weight every week, especially not 5lb. And as you get closer to your ideal weight you will find it harder. Just keep what you are doing and expect some weeks to be better than others. As Eric said do some more weights. Also, if you build muscle, you can lose fat but not lose any weight. 200lb toned is different to 200lb with a gut, so focus more on how you feel and look than what the scales tell you.

667f6c030b0245d71d8ef50c72b097dc

(15976)

on June 13, 2011
at 02:24 PM

I'd agree. Mirror and camera with the same lighting is much more effective than using only a scale. I do weigh myself and I'll admit that I start tinkering if I see too much weight gain too quickly but a mirror is more useful, especially if you are doing activity that is actually building muscle.

2
1a98a40ba8ffdc5aa28d1324d01c6c9f

(20378)

on June 13, 2011
at 04:46 AM

Gaining muscle aids in weight loss. By doing squats and deadlifts and bench press you can add muscle. Or with dumbells at home you can still work the legs and arms. I would say doing this would aid in weight loss and also keep your walks under 45 minutes and perhaps walk some hills.

2
77877f762c40637911396daa19b53094

(78467)

on June 13, 2011
at 04:33 AM

I worry about that long of a fast. Will you consume water and or tea? But I say try it and see how you feel. If it sucks then adjust your diet. But don't think your weight loss will be as quick as the first two weeks. It can take months and should take longer if you are in a diet that is for sustainability.

Fc7712b6a931b618ffaf4d6475b5d8f4

(200)

on June 13, 2011
at 07:37 AM

Lots of water and tea!

667f6c030b0245d71d8ef50c72b097dc

(15976)

on September 07, 2013
at 01:28 AM

I too would hesitate before going that long. Our bodies can handle the occasional 24 hour period but there's not much research indicating that we are suited to fasting longer than that. Even if one is completely adapted to burning fat, and not suffering from blood sugar issues, they are going to have serious hunger pangs after that long. Which I would say is going to interfere with normal functioning throughout the day. I'd think one would become too focused on food food food after that long.

2
E7be2ce38158357f5dacae07b43d1b29

on June 13, 2011
at 04:27 AM

Everything I've heard/read/experienced about fasting for a few days has always been positive. I suppose if you have serious health issues that are based on lack of nutrition, then fasting might be negative, but there is a lot of scientific and anecdotal evidence out there to suggest that fasting over many days can be a healthy purge for the body.

I haven't done personally done much more than a day, and am hoping I can muster up the fortitude to do at least that again soon... I could really use that kind of "reset" right now...

-1
1a98a40ba8ffdc5aa28d1324d01c6c9f

(20378)

on June 14, 2011
at 05:59 AM

Another approach that burns calories like crazy:

Each meal eat one large piece of protein about the size of your palm. And enough broccoli, spinach or cauliflower. Other vegetables would work as well...

For the protein eat chicken, beef, bison or wild salmon.

This really works because protein requires energy to digest and the fiber in the veggies sweeps some of the food away undigested.

Do this for three days a week instead of fasting and exercise as well and it will help you lose weight.

1a98a40ba8ffdc5aa28d1324d01c6c9f

(20378)

on June 15, 2011
at 02:59 AM

Too Funny. It is sort of like: http://robbwolf.com/faq/ Look for fat loss. Indeed pretty standard eating. Maybe palm and fingers :-)

667f6c030b0245d71d8ef50c72b097dc

(15976)

on June 14, 2011
at 12:51 PM

umm, how is this not just normal eating? Does anyone on these boards ever have a meal that does NOT have a large piece of protein. (btw, size of your palm? huhwut?! I think i need bigger palms)

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