Charmayne, I'm also quite surprised myself, given that I'm quite a good eater even during pre-pregnancy. Still eat the same portions except for additional mid-morning and mid-afternoon snack, but I guessed one thing that helped the weight was perhaps I consciously skipped sweet stuff like cakes, desserts and chocolates which used to be my favourite. At 16 weeks when my weight gain was less than 2kg, I checked with my doc if this was too little and she said its alright as long as baby's growth is on track and it's ok to go without weight gain till 5th month.
Clarise, I also haven't bought much baby stuff yet, except for a baby carrier and few pieces of home clothes. Hopefully will get down to it before end of second trimester, advised by my friends to get most stuff by then before our energy levels dip again.