After weeks of searching, I think I've found a food diary app that suits me. It's certainly different from any other I've seen. It's called CountEat.
The thing I've always hated about food diaries is that you have to break down and analyse every single food you eat - 1 tsp margarine, 2 slices bread, what type of bread, how much did it weigh, etc. etc. Spending ages each day, entering it all in: I spend too much time thinking about food as it is. Boring, boring, boring! Stressing, depressing and not to mention annoying!
With this app, you look at the whole meal instead of breaking it down into individual ingredients. Foods are divided into 5 Categories, depending on how many calories they have overall. There are lots of example foods for each category, so it's easy to decide which one my meal falls into. Of course, it works best when I'm honest with myself - and I think I am (most of the time!). The app calculates the average amount of calories in the meal and tells you an estimate of the total you ate for the day. A slider shows my healthy eating range and whether I ate 'too much', 'a healthy amount', or even 'not enough'.
The app won't tell you any exact amounts, only an estimate. But an estimate, a guide, is all I've ever really wanted. Just so I know how I'm going and where I might need to improve. I've only been using it for a few days, but it's really working for me. So this is good.
Now I just need one that tracks my exercise. Still working on that one.