There's more if you start going your way. You can infer a lot of things from shopping records, particularly when you're shopping couple times a week (vs. bulk shopping once every week or two). The things you buy are informative, but so is how your purchases change over time, and so are the dates and times you make those purchases.

Some extra things that should be easy to infer: on what dates were you going to a party; on what dates you had a hangover; when did you go on a diet and how good were you at sticking to it; if you have a problem with alcohol, when did it start and how it progress; are you dating someone; are you planning to travel. I could go on and on - all those things can be identified if you have a continuous record of a regular customer's purchases. And there are many companies, organizations and individuals that would make good use of such inferences - use of the kind you wouldn't want to be subject to.