It's a confounding question: If we're becoming more health-conscious, and healthy alternatives to our old, fatty, high-calorie mainstays are sprouting up in restaurants and grocery stores across the country, why on earth are we getting fatter?

That's the question taken up by two researchers in a project examining what they call the "health halo," and reported by John Tierney of the New York Times.

Dr. Pierre Chandon, a Frenchman, and Alexander Chernev, who teaches marketing at Northwestern, designed two questionnaires to test their hypothesis that the health push has backfired on many Americans because of one of our greatest talents: rationalization.

Their first questionnaire depicts two items -- an Oriental chicken salad and 20-ounce cup of Pepsi -- and asks respondents to guess how many calories are represented. On average, they found that Americans guessed about 100 calories too many. Big deal, right?

Now for the ironic part: Questionnaire number two depicts the same two items, but adds two crackers, advertising their lack of trans fats. This meal earned guesses that fell below not only the estimates for meal one, but also the actual number of calories in both meals.

That's the halo effect. People see "No Trans Fat" and suddenly believe the meal is healthy. It's the reason diners at Subway are more likely to consume higher-calorie meals than McDonald's patrons: while people who eat at McDonald's know what they're eating is junk, people at Subway think the opposite and thus feel they can "afford" those three white chocolate and macadamia nut cookies after they put away a 12-inch hoagie. In the end, the McDonald's diner walks away feeling a little guilty, perhaps, but better off than his "health-conscious" pal who jumped into Subway on their lunch break.

The most interesting part of the study, I think, is that European tourists who took the test in Times Square rightly guessed that meal number two had more calories than meal number one. Why? Because, the researchers suggest, the term "trans fat" means nothing to them, so they aren't blinded by its promised lack.

[Image: EncylcoPetey for Wikimedia Commons]