After about 24 hours I don't notice anymore. I just finished a 2 week fast on only water, tea and supplements. I hardly notice when I focus on something else (work/hobby). When I stop focusing I get sleepy instead of hungry. Cold I have not managed; I come from a cold country and I really really hate any type of cold; I like 30C+ high humidity as a baseline, under that, I am cold and uncomfortable. I did try to view them the same and tried to meditate through it, but, unlike fasting, I cannot ignore the continues suffering that is cold while fasting is almost pleasant (makes me sharper).