I just don't know what the solution is. I guess you could force them to break up somehow but whichever entity is smaller is probably not going to be able to compete.
We have a big four supermarkets in the UK, plus another four or five second tier chains, and they still managed to bury the hatchet long enough to pull this shit on consumers, blaming gas prices, and then announce record profits.
I they to buy from my local green grocer as much as possible, and try and get meat from the local butcher. Most of the time it's even cheaper! My little town doesn't have a good farmer's market, but that's a good option as well.
Honestly though, people are too in love with convenience to do anything about it.