Hi all.
I don't know if it depends on what your previous diet consisted of, and for how long, but it took me several years of eating high fat paleo to bring my body temp. back up to normal and to get my free T3 back into the normal range. I was always cold as a vegetarian, freezing as a sick vegan. Now though, six years after becoming an omnivore again, I'm ready to move to Canada or Alaska I'm so warm! I've kept my carbs at around some 20-50g for a couple years now, (which BTW, has put my Crohn's in remission) and I'd say that's the period at which I noticed the most change in body heat.
Lois