Check out this link. http://www.leangains.com/2010/09/eat-stop-eat-expanded-edition-review.html

In the book review Martin has a section entitled "fasting and cold fingers"

The basic idea is that during fasting your blood circulation is centered around your abdomen and less blood circulation to the extremeties. He believes it is nothin to be worried about. It can be helpful (says Martin) because during the fast you are attempting to rid yourself of abdomen fat and the enhanced blood flow speeds this process. Don't take my word for it though, read the site.

I get cold sometimes when fasting. It seems to be happening less and less. My take is to put on warmer clothes and stick it out. Of course you should never do something you feel is harmful to your health. If you are having issues with fasting maybe you should start with a fast for a shorter period of time and extend it gradually over a few weeks to acclimate.

I can get a bit cold during long fasts, i believe the body is just being careful with it's energy reserves. I don't see this as a problem, and it is even rather pleasant during the summers.

A quick spot of movement or exercise warms me back up. Wool socks can help, too.

Not really big on fasting, but for me, I've noticed I get cold a lot easier when I'm cutting the calories. I always attributed it to the metabolism running a bit more sluggishly without the extra calories.

When fasting your body is answering by conserving more energy and that translates in less body heat. That's a first common sign of the body in energy conservation mode. I you were to fast for an extended period of time, you would get even colder, then would have less and less energy and eventually even climbing stairs would seem like a chore.

This is normal, but I think that it can only get better with time and your body getting used to be efficient with its energy.

Funny i stumbled across this today...yesterday i fasted for 24 hrs and at about hr 16 i too became cold and couldn't warm up, but actually was getting colder. I even turned the heat up in the house and the wife was super surprised. I am 6' 192lbs with 7% BF...all of thses answers make sense. Thnx for all the input hackers!

http://raypeat.com/articles/articles/hypothyroidism.shtml

A study by Johnson et al in 1982 showed that the subjects on a calorie restricted diet or intermittent fasting program were leaner and more active yet more vulnerable to cold. Fortunately, unlike, the small animals used in these tests, we have ample methods of keeping warm and this, although an expected side effect, is not to be concerning.

I am freezing right now and I'm three hours from being done on a 24 hour. I have fingerless gloves on but I am so cold. I had to take a bath before bed and I just laid there for 2 hours shivering.

im muslim and i'm fasting for about 18shours this ramadan, just googled cold and fasting and this came up.

why are you lot fasting is this part of your religion too?

my mates dad was a rastfarian and he would randomly fast because he said it's good for the body but this was not aa obligation of his religion.

Fasting reduces body-core Temp,the body conserves energy by pushing circulating blood to the major organs,this is logical and normal.Those with less than 10% body fat will feel it more. People may also notice an increase in blood pressure while others notice a drop in pressure. this is way fasts should be supervised by someone whom knows the warning signs for certain individuals that may get into potential serious problems.

Anyone whom has never fasted before or whom has known health issues should always be supervised and monitored by a health care professional.such clinics do exist such as true-north in the USA and I myself supervise individuals www.bodybudddha.co.uk.

I too get cold when fasting. I do daily 20/4 windows, and 16/8 windows on lifting days. Works ok for me though, since I live in the desert southwest and summers get into the 100+ temps. :)

Studies have shown that metabolism actually increases when fasting, at least during the first 24-72 hours. More info on that at leangains, just search for Top 10 Fasting Myths Debunked article. So, it's unlikely the coldness is due to reduced metabolism. Though I don't have an answer for it.

By the way, when I have my big pile-o-chicken breast at dinner, I warm up quickly. :)

I seem to get really cold every time I eat. I have Raynauds's disease i.e. thick blood that finds it hard to reach the extremities. I'm having green tea for breakfast, poached eggs with spinach for lunch and whatever I like for dinner. I've just had my eggs and my body temperature has shot down and I can't feel my big toes, which have changed colour. Last two days I've had to have a bath after dinner to warm up. Its only four degrees outside but that's warmer than the last few weeks, although not all the snow has melted, it is sunny.

I just think what little energy I have is concentrated around digesting my food, but seriously, two eggs and some spinach, how much energy does that require?