When asked for nutritional advice the first thing I require is a food diary for two weekdays and a full weekend.
Usually the act of writing this diary brings about a realisation in the author of what they shouldn't be eating and what bad habits they've fallen into, so they don't even need to be told what these are.
I think there's something about writing things down that make you face up to reality, but even more so if you know it will be read by someone else.
Still there's no need to fork out on an expert to read it - just buddy up with a good friend who you can be totally honest with. At the end of every day send your bud a quick email of your food and exercise diary for the previous day.
It'll quickly shame you into clearing up your bad habits. Plus you might develop some healthy competition and spur each other on!