A recent report that got widely disseminated claimed that “that subjects who ate chocolate more frequently had lower body mass index compared to those who consumed it less often, and this was not affected by taking calorie intake or level of physical activity into account.” The notion of chocolate as a new weight-loss strategy obviously has it appeal but what about the science behind this study and the methods applied?
Geoffrey Kabat, author of Hyping Health Risks: Environmental Hazards in Daily Life and the Science of Epidemiology, questions the basis of the study in a recent op-ed in Forbes, The Bad News About the Good News About Chocolate .
In the piece, Kabat questions and faults the way in which the study was conducted:
This is a cross-sectional study, meaning that the information analyzed was collected at one point in time. Thus, it tells us nothing about weight gain or weight loss or factors contributing to these changes.
Furthermore, the researchers obtained information about the usual consumption of over a hundred foods by means of a “food-frequency questionnaire.” The authors do not tell us how many other food items and other behaviors were correlated, either positively or inversely, with body mass. What about nuts, broccoli, jello, coffee, beer, veal? What about the frequency of other behaviors – going to the movies, sexual intercourse, ice-skating?
Likewise, other variable such as socio-economic status of the subjects were also ignored, relevant here because wealthier people, with more disposable income for chocolate tend to be leaner. However, as Kabat points out, there is a larger issue at stake, namely our desire for “magic bullets” to serious problems like weight gain tend to sacrifice careful scientific research. Geoffrey Kabat concludes by writing,
It is in our nature to look for magic bullets that would allow us to circumvent hard realities – like that of energy balance. But science is supposed to involve a critical approach to a problem, rather than pandering to our illusions.
As we recently learned from the now-discredited report that appeared to violate Einstein’s dictum that nothing can travel faster than the speed of light, when the results look too good to be true, they probably are.