Because he's going through a fussy stage and just seems to want the same stuff.
We usually offer whatever we are having but end up giving him something like toast soldiers with veg sticks, hummus and a side of fruit or pasta with tuna or chicken/ham etc..
Do they all go through this stage of seemingly only liking a handful of things?!
He adores fruit of any kind but struggles with veg although I try and offer it with every meal and he will have a small amount namely cucumber, sweet potato or sweetcorn.