My suggestion is eat when you are hungry. Your body will you know when you need to eat. I know people that didn't eat a lot while pregnant because they weren't hungry and had normal pregnancies and normal size babies. However, I eat a lot normally so...lol.
I am 13 weeks this week and it seems like last week my food aversions just got worse even though everyone says they should get better. Just try to eat what you can, when you can. For instance, yesterday I had a bowl of cereal of breakfast, applesauce for snack, an egg bagel for lunch, and a bowl of cereal for dinner. So far today, I had a bowl of cereal this morning, applesauce for a snack, and a sub for lunch. Dinner is probably going to be a bowl of cereal again. Night is usually when my nausea is worse so I don't usually eat much for dinner. Try eating something every 2-3 hours. Applesauce has been great for me. It isn't too rich, no smell to it, and it just slides down real easy. It is easy on my tummy and doesn't make me want to run to the bathroom.
I spent my first couple of months in porcelain heaven. For the last couple of weeks, while Im not throwing up, I have no interest in food. Knowing that I need to eat, I try to eat a small something every 2-3 hours. It may just be a piece of toast with peanut butter, some rice, crackers and cheese, or a piece of fruit. I am never hungry, even if I didnt eat, I dont think I would get hungry, I dont have an appetite, or thirst either which is strange. I am at a point where I force myself to eat because I know that the baby needs it. When it comes time to eat I just try to pick the least offensive of all foods in the house, whatever that is at the moment. I dont have any specific suggestions other than that, because I know everyone is a little different. Try to remember only 4 more weeks til it should be all better. Try to eat, even if just tiny bits, hang in there, it will get better!!!