DHM~ 1st trimester is from 0-13 weeks. My Gynae told me to take folic acid now. I remember calcium n DHA was for 2nd trimester on (n continue if breastfeeding). My Gynae is super cool about food restrictions (unless under special instructions fr him that cannot) - cold food n drinks/fizzy drinks/a bit of coffee a day.. In short, whatever u feel like eating or drinking, jus go ahead. But I still stand by the no raw/half cooked meat/not too much fish n no raw veg n half cooked eggs. There's a good app 'Food no-no's' for preg mummy. I find it useful.
For my 1st preg, I only had cold Ribena n magi mee for the first trimester. Was vomiting so badly. So glad that for this preg, am able to eat everything. Even had a huge bowl of laksa for dinner yest!