Jacob's mum - that's brilliant - I know you are going through a tough time right now - I have heard about judging it on a week by week basis rather than a day by day, and I try and do the same (I think child nutritionists would do the same). I also know of one little girl who eats like a *horse* and is skinny as anything, and another wee girl who is a really, really picky eater, but she is average weight, height, energy, intelligence, everything!
Best not to judge against any other kids and just do your best - and don't worry about 'giving in'. If Katie is fussing for dinner before it is ready, I give her her 'pudding' (yoghurt or apple or pear or whatever) first, so she has something to nibble on. TBH, if she asked for some crisps before dinner because it wasn't ready, I would probably just give her them, but just not too many - crisps are potatoes after all (I know, not a great reason to give them to them!).
Our Katie has days where she eats great and days where she doesn't - to give you some idea (even though I have just said NOT to compare to anyone else!), this might be a 'typical' day (bear in mind she is 25 months old and weighs about 30 lbs - she is 75th percentile for height and weight):
Breakfast - watered down juice, maybe half a slice of toast, maybe nothing
Snack - fruit (maybe 3/4 or a whole pear), or 1/4 cereal bar, or a biscuit
Lunch - maybe 1/4 ham sandwich, maybe some crisps, maybe some yoghurt
Snack - some raisins
Dinner - a 'baby' bowl of pasta with sausage and veg puree or whatever - i.e. one of those toddler plastic bowls - sometimes eats all, sometimes eats half or even a quarter (or less), maybe some yoghurt and fruit
Before bed - lots of milk
So, overall, I don't think this is an awful lot to eat at all and I am constantly amazed that she has maintained her height / weight / energy / fun. But, this seems to be what works for her. We as mums have to trust our LO's internal metabolisms - it is very, very hard to do (especially if you come from the same camp as me where you were taught to eat everything on your plate - hence why I am a good 20lbs overweight!).
Good luck and try and chill a little - your wee one is doing brilliantly!
xx
PS - I tell people at my work about times when Katie has tried something new to eat - LOL!