I do not do any diary, in an form...no butters or creams. I have coconut milk and oil, olive oil, fish, meat, tons of veggies, but I still am only getting 1500 calories a day, and I'm not hungry, I run 3 miles every other day, and I'm ALWAYS COLD, I've been usually colder than usual my whole life though. I only have a sweet potato mash high calorie recipe but I want more variety.
I don't do nuts or nut butters.
Not a professional, but that certainly sounds like a thyroid issue. If I was you I would lightenin up on the running for a bit and start considering supplementing things to boost your metabolism.
On a related note, when I supplemented with iodine I actually felt noticeably warmer immediately after consuming the supplement. ( Be careful with the supplements )
The obvious paleo answer would be to drench everything in oil or other forms of fat.
The obvious non-paleo answer would be to consume sugary/carby food, as people seem to think these cause people to over-eat. If you want you could even consume a sweetened beverage, these are known to not impact the fullness of an individual and just increase their caloric load. ( brush your teeth )
Yup, iodine, selenium, and L-tyrosine, and possibly dessicated thyroid for the win - but only if you've ruled out Hashimotos first. Get checked for antibodies first before supplementing, or you'll wind up in even worse shape.
In case you're consuming enough (and not fasting) then I don't think you ought to be feeling COLD. Track your day by day macronutrient admission. I think you are not consuming enough protein and fat. Protein supports in legitimate thermoregulation and keeps your body agreeably warm.