Ok - On a work day in my 3rd trimester this is what I usually ate:
Breakfast: porridge made w/ water + some dried coconut and seeds sprinkled in. Topped with a drizzle of honey and half a chopped up banana
Lunch: Salad of greens, veggies, tuna, feta, quinoa w/ olive oil and balsamic
Afternoon snack: wholemeal hotcross bun + 2 small clementines
Whilst cooking supper: Carrot and lashings of hummus
Supper: something like homemade beef chilli or green chicken curry w/ brown rice + a few dried figs for afters
(Note, on most days a bit of chocolate thrown in at some point too). Other regular staples include homemade soup for lunch, smoked mackerel, baked potatoes.
But many some days deviate from that quite a lot. And in my 2nd trimester I had a monster appetite and ate masses and indulged all my cravings (2nd tri also coincided w/ a long holiday and then Xmas, so all willpower escaped me). But, I've always been a relatively healthy eater (albeit one with a raging sweet tooth), and I begin to feel a bit weird quite quickly if I don't eat enough fresh veg. My general approach to eating is to avoid processed food, anything with too much added sugar (breakfast cereal is a real killer here - never eat breakfast cereal!), anything labelled 'low fat' etc (usually packed with other crap to make up for it) and to try to cook or make from scratch most of what I eat or get the shop-bought version with the least amount of ingredients (e.g. bread). During pregnancy I've been quite enjoying listening to what my body wants to eat. E.g. in my 1st tri, all I could stomach for breakfast was eggs on toast, now at 37wks I've gone right off eggs, etc. Go with the flow, try to be sensible and balance out the sweet treats with plenty of the good, nutritious stuff and you'll be good!