From what I know.....

Fall is the traditional time to put on weight to ptep for the winter famine.We are preprogrammed for this.

Feeling the cold is part of the physiological changes to cope with colder temps. (Just as the spring warm days feel too hot.) It could also be an indicator of low thyroid. Some people seek thyroid medications or figure out what is driving thyroid hormones low.

As for feeling low energy, that could also mean the veginning of tge seasonal blues. While I took a low dose Vit D3, it helped but did not eliminate my SAD, not the food,lol, but the seasonal blues. Jumping to 10,000 units of D3 made all the difference. What I do is make sure Im at that level as of Sep 21 as I live in MA, USA.

Others are sure to have more ideas.