Hi All,
I have determined that I was fasting (long term and intermittent) too much and was getting too cold. That is, my hands would be FREEZING when fasting not even 22 hours. When I ate, this went away basically immediately. So, I’ve taken time off from fasting and am trying to eat 2 meals (or more, if I’m hungry, but it’s usually only 2) per day.
How do I know I can restart fasting? And when I restart, should I jump into a longer term (3-4.5 day) fast, or maybe only keep it to 36+ hours?
Probably best to start with IF for a while first and see how you go before trying to do anything longer.
How long Keto? (Fat adaptation)
How much body fat? (Fat availablility)
How much experience fasting?
The first two tell you how well you can fast. The last is just experience - exercise the fasting muscle!!
And when fasting, keep the body guessing. Search “switching it up with Medan Ramos” on 2KD podcast
But, were you hungry?? I have the same problem, but I’m sitting outside and it in the 50’s. heating up my water helped me. How often are you fasting?
Low carb since 1/1/2014. Keto most but not all of that (forays into paleo, resistant starch), keto for a while now. Started intermittent and long term fasting spring/summer 2015. Started skipping bfast 2 days per week, then having bullet proof coffee and skipping lunch, then skipping bfast and lunch, then multiple day fasts. Have done 10+ (or 15+?) 3-3.5 day fasts, 5+ (8?) 4.5-5.5 day fasts. Was having more trouble over time doing longer fasts (couldn’t finish them), so went to shorter fasts. Started doing 2 36 hour fasts and 1 22 hour fast per week. No longer eat bfast, except on rare occasions.
Have increased my exercise, at the same time I’m doing home improvement projects all weekend. Exhausted on Mondays. Tried to IF one Monday after HIIT Saturday, then working on home improvement project all weekend, and was FREEZING by noon. It was all I could do to make it to dinner.
Was I hungry? Possibly, but I’m pretty much always hungry when fasting. It goes in phases. Sometimes hungry, sometimes not. I mean, you can’t not eat for 4.5-5.5 days without being hungry at some point.
I do know that when I finally decided to quit IF and LTF (long term fasting?), I ate a “blunch” (my normal breakfast/lunch, normally only have 2 meals). Then I had more, and then more. I ate 4+ times that day, well over a pound of shrimp, 1+ pound ground meat, a bunch of other food, and that was BEFORE dinner. At that point, I realized I was not getting enough food in me.
I’m disappointed in Dr. Fung’s fasting book. There is ZERO information I can find in the book about fasting too much. I can find one answer by him to a question about getting cold, and he said to eat more during refeeds. Nothing about having consistent cold hand and similar effects every single time I try to fast more than 18 hours. I realize now that I was underfed, but there should be something in his book addressing this. I listened to his podcast, and he had 60+ year old women on there fasting 3 days each week. I thought to myself, “If they can do it, I can do it!”. 
Anyway, I’m going to give it another week or possibly more, as I can still feel a slight coldness come on if I wait to eat much longer than say a few hours after a workout.
I have the same issue. I track my body temp and cut off fasts when I’m 1.5F or more below normal. I’ve found tea with coconut oil (or coffee with cream) can help if my temp is dipping.
I understand that if you feel significantly cold during extended fasting that it is a sign that your BMI is dropping. You can either stop your fast and refeed making sure to get plenty of fat or just consume enough fat until it passes and resume fasting when your body temp increases.
If this happens repeatedly, taking three or four days to do a modified fat fast for three or four days prior to your extended fast as described in this IDM post:
https://idmprogram.com/what-is-fat-fasting-and-when-should-you-do-it/
Do you have a history of Renauds? Have you ever been tested? Is it only while fasting?
Another thing to check is thyroid function. I found that adding kelp tablets for iodine (iodine is necessary for proper thyroid function) helped, and I get less cold when fasting for extended periods.
If you don’t use iodized salt, it’s possible you’re not getting enough iodine.
There are blood tests that can help assess thyroid function, and it might be worth checking that. Probably an area where it makes sense to work with your doctor.
Thanks, all. I’m still working on it. I only get cold when fasting. As soon as I eat it goes away. I’m usually hot when not fasting, though that has also changed with 50+ pounds gone. I’m no longer as “hot” as I once was.
Today, I got up really early (not sure why), and was not actually hungry, but got cold. Because I got cold, I ate. As soon as I ate, I turned on my fan, because I’m now hot! 
I will definitely get my thyroid checked, but my understanding is you have to get a “good” test done, and then find someone who can interpret it. That’s the kicker – it’s like trying to find a doctor who believes in low carb. It’s nigh impossible.
I don’t really have any of these symptoms:
https://www.mayoclinic.org/diseases-conditions/raynauds-disease/symptoms-causes/syc-20363571
So, I don’t think I have Raynaud’s.
I think I perhaps overdid fasting. I did not know that was possible, but it seems to be the case for me (unless my thyroid comes back differently).
Also relevant (should have posted this earlier):
If you have insufficient fat stores than what will allow you to supply your daily energy requirements, that could definitely affect your metabolism, which might include getting cold.
I’d ease into it, yeah. Or plan for five days and then quit after one if you’re cold again, same same 