(Saher et al. 2004) evaluated the impressions people developed based on shopping lists that had "either healthy or neutral background items, conventional or functional target items".
They concluded:
Buyers with healthy background items were perceived as more disciplined than those having neutral items on the list, users of functional foods were rated as more disciplined than users of conventional target items only when the background list consisted of neutral items. Buyers of functional foods were regarded as more innovative and less gentle, but gender affected the ratings on gentle dimension. The impressions of functional food users clearly differ from those formed of users of conventional foods with a healthy image.
A similar study by (Stein et al. 1995) used food lists rather than grocery lists. They had participants "read a profile of either a female or male target including information about the target's preferred foods". They found that "[r]egardless of whether the target was male or female, targets described as preferring “good” foods were rated as more feminine and less masculine than were targets described as preferring “bad” foods."
(Barker et al. 1999) also used food lists rather than grocery lists. "Subjects were
then asked to recall systematically and describe everything they consumed the day
before, starting with when they got up." Subjects were then split into a high-fat or low-fat group. "For the assessment of stereotypes, subjects were presented with lists of one
high-fat diet (A) and one low-fat diet (B)".
Subjects were then
given a list of adjectives and descriptors presented as sets of antonyms, and asked
to select appropriate adjective/descriptors from the list to describe consumers of
diets A and B. There were 27 sets of antonyms: attractive/unattractive, interesting/
boring, intelligent/unintelligent, easy-going/highly strung, happy/unhappy, healthy/
unhealthy, sociable/antisocial, friendly/unfriendly, prim and proper/unconventional,
outgoing/shy, energetic/lazy, outdoorsy/couch-potato, sporty/inactive, physically fit/
unfit, fun-loving/serious, modern/old-fashioned, generous/selfish, ambitious/unambitious, politically correct/outspoken, slim/overweight, male/female, young/old,
employed/unemployed, single/married, non-smoking/smoking, non-drinking/drinking, working/middle/upper class.
(Barker et al. 1999) reached several conclusions. I'll quote two that I found interesting.
Overall, subjects were significantly more likely to choose negative descriptors to
describe a follower of the high-fat diet and positive descriptors for a follower of the
low-fat diet.
It seems that people with high-fat intakes
characterize high-fat consumers using positive and negative stereotypes, while people
with low-fat intakes characterize high-fat consumers using negative stereotypes only.
Also not about grocery lists, but about consumption stereotypes in general, (Vartanian et al. 2007) is a comprehensive review paper on "empirical research on stereotypes based on what and how much people eat". That paper provides myriad references to other work showing consumption stereotypes along the line of "you are what you eat" and "you are how much you eat".
The meta-conclusion they made about stereotypes associated with "what you eat" is:
Overall, it appears that trait attributions emerge independent of target or rater sex, such that, for example, women and men are judged as being more feminine and less masculine when they eat low-fat foods than when they eat high-fat foods. In addition, there are somewhat mixed perceptions of low-fat-food consumers: On the one hand, they are seen as being intelligent and moral; on the other hand, they are also seen as boring and not particularly fun to be with.
References
Barker, M. E., Tandy, M., & Stookey, J. D. (1999). How are consumers of low-fat and high-fat diets perceived by those with lower and higher fat intake?. Appetite, 33(3), 309-317.
Saher, M., Arvola, A., Lindeman, M., & Lähteenmäki, L. (2004). Impressions of functional food consumers. Appetite, 42(1), 79-89.
Stein, R. I., & Nemeroff, C. J. (1995). Moral overtones of food: Judgments of others based on what they eat. Personality and Social Psychology Bulletin, 21(5), 480-490.
Vartanian, L. R., Herman, C. P., & Polivy, J. (2007). Consumption stereotypes and impression management: How you are what you eat. Appetite, 48(3), 265-277.