I'm going to go a little against the standard grain of "It doesn't matter, you're pregnant, anything goes" advice. You can choose to eat however you like during pregnancy, but it's always going to be your choice - you don't suddenly lose all control over what you eat when you get pregnant!
It doesn't matter what sort of food groups you're eating in your first trimester (why are people so obsessed with carbs anyway??) - what matters is how MUCH you are eating - just like at any other time in your life.
You don't need any extra calories in the first trimester - if you are feeling nauseous, then you have to do what you need to, but obviously relying totally on food will inevitably lead to gaining more weight than you might need to.
If you feel hungry even after eating, then it isn't hunger and there's not much point constantly eating through it! It's just a really shitty part of morning sickness! Personally I found really cold water helped, but obviously different things for different people.
People will take different mind sets to weight gain in pregnancy - some people like a pp choose to not know how much they've gained, and instead make plans for losing whatever they need to in the future. Others will indulge however they want and just hope they can lose it afterwards, but don't seem to stress about it too much in the mean time.
Personally I can't think of much worse than having to try and lose a significant amount of weight when I'm massively sleep deprived and trying to navigate a newborn, so I prefer to keep an eye on my weight whilst pregnant to make sure I stay within the recommended guidelines.
There's no "right" or "wrong" approach, so long as you don't take the attitude that it's something that just happens to you of which you have no control over!