It's a Long flight, we don't tend to get many complaints about the catering, moreover I would suggest it is a somewhat better meal than some USA airlines would provide (if they provide any at all), albeit this is a subjective perspective.

OP - if you want to avoid this, your only likely realistic alternative is to fly via IST or beyond. TK has wider seating and is one of the few in this part of the world to have dedicated premium seating. That said you need to be careful since ATH-IST is one of the few routes which can occasionally have similar (or worse!) seating to BA. Alternatively arrive into Greece on a longhaul service, such as Delta's JFK service to ATH.