Kelly L. Haws, associate professor of management at Vanderbilt's Owen Graduate School of Management and her colleagues conducted a series of experiments that involved presenting participants different snack “bundles,” consisting of varying proportions of “virtue” and “vice” foods. For instance, one of these virtue-vice bundles took the form of a plate of three-fourths salad and one-fourth fries, another a plate of one half salad, the other half fries.
In the first study, participants were offered a choice of a healthy snack (apple slices), an indulgent snack (fries), or a mixture of the two, and asked to pick their preferred munchies combo. In the second study, subjects were presented with similar vice-virtue bundles, but this time the researchers also measured whether the participants actually ate their snacks, and ascertained whether their choice of healthy, unhealthy, or mixed snacks affected their post-experiment eating habits. In a third experiment, participants were asked to rate the perceived healthiness and tastiness of a series of healthy, unhealthy, and mixed side dishes, and then chose their ideal snack plate from the options at hand. In a fourth and final study, participants were again asked to choose between various vice-virtue bundles, but were not given a 50/50 option — the goal was to see whether people would gravitate more towards the mostly healthy option or the mostly indulgent option in the absence of a perfect balance.
Overall, the researchers found that people have what they deemed a “taste-health balance point” — their ideal ratio of vice to virtuous foods in one serving. Most people do prefer a little indulgent food in their life, the key word being little. In order to be satiated, we only require about one-fourth to a half portion of our plate to be foods we eat for enjoyment. In addition, the researchers found that people who normally gravitate towards self-indulgence fare better when offered a vice-virtue combo — their caloric intake subsequently decreases. For those of iron will, who actively prefer carrots to fries either on the basis of taste or health, being offered a little bit of both can cause a slight, but not significant, increase in caloric intake.
Of course, there are certain limitations to this research. The first two experiments dealt solely with college students, who admittedly may not be as health-conscious as those dealing with slowing metabolisms and other age-related concerns. Secondly, this may be a personal feeling, but fries are not necessarily the end-all-and-be-all of tempting non-nutritious foods. Finally, our systems and decisions are heavily influenced by genetics and unconscious influences in ways scientists are still struggling to comprehend. In the long run, though, we can’t take objection with a diet based on compromise, with a skew towards the healthy side. Go ahead and eat that fry.