The posher restaurants are easy enough to eat in as you can chose what you want. It's the cheap and cheerful ones find difficult - eg eating at pubs - as everything seems carb-based / carb-accpmpanied or drenched in sugar sauces.

For something cheap and cheerful though, I like the Nando's chain - which specialises in marinaded grilled chicken - as you can have yummy grilled chicken and a big salad