There's no trendy food on Ko Sichang, but it is a great place to eat. First and foremost, we recommend Pan & David, about 200 meters before the palace entrance. Read at left to find out why we like the place so much.
There are a lot of other places you can get good food, especially seafood. The island's fleet of squid boats makes squid here seems like a completely different thing from what you get in Bangkok. We don't bother to order it anywhere off island. Several places have live crabs, too, and very big (up to about 180 g each) prawns--all cheaper than you're likely to find at the big-name destinations.
Apart from the places listed below, there are dozens of noodle shops and pushcarts for a quick snack, usually pretty good value, too. And if you're dying for air conditioning, there's a coffee shop at the Sichang Palace Hotel.