Tuesday, January 22, 2008

Understanding the French Obesity Paradox

The French eat more fat, are less diet obsessed but also less obese than Americans; a new study has found a reason, possibly the most important one. It is about the cues that lead a person to stop eating. For this decision, the French rely mostly on cues from the gut, the Americans from the environment. This is the outcome of a study on internal and external cues for meal cessation. Looking at this dish of ratatouille, a French probably will put it aside because he feels full and a dessert is yet to come while an American may feel that it's normal to finish such a yummy meal.

Different food worlds in Paris and Chicago

Two groups of college students, more than a hundred in each group, have been surveyed, one in Paris and one in Chicago. They had to rate how strongly they agree or disagree with the following statements:

  1. I usually stop eating when I start feeling full.
  2. I usually stop eating when I want to leave room for dessert.
  3. If it doesn’t taste good, I’ll still eat it if I am hungry.
  4. I usually stop eating when I’ve eaten what most think is normal.
  5. I usually stop eating when I run out of a beverage.
  6. I usually stop eating when the TV show I’m watching is over.
The first three refer to internal cues, coming from feelings of the gut. The last three refer to external cues, coming from the environment.

The most significant correlation (p-value less than 0.001) was that Parisians relied mostly on internal cues and Chicagoans mostly on external cues. Another correlation was also strongly significant (p-value 0.005): Students with a higher body mass index (BMI), regardless of residence, were more influenced by external cues. Despite some limitations of the study, for instance BMI only self-reported and not measured, not controlled for smoking, not a representative sample of the whole population, the findings are quite telling.

Don't let them super size you!

Given these findings, it is very easy to understand why fast food companies sell ever bigger portions: This strategy works very well with Americans because it exploits their reliance on external cues. Much has been said about public health efforts, for instance advertising bans, to alter the "obesiogenic environment". I am not a fan of this approach, and I feel assured by this study. If U. S. Americans manage to listen more to their guts, they may learn to push half-eaten super size burgers aside to leave room for dessert.


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