Is obesity related to the type of dietary fatty acids? An ecological study.

Background: Animal studies and a few clinical trials lend credibility to the hypothesis that not all types of fatty acids carry the same potential for weight gain. Only a few epidemiological studies concerning this issue are currently available and results are conflicting.

Aim: The purpose of the present ecological study was to test the existence of an association between obesity prevalence and the types of fat available in 168 countries.

Methods: Data on the prevalence of obesity (BMI >or= 30 kg/m2) for women over 15 years of age were obtained from the WHO Global InfoBase. Food balance sheets for the years 1998 to 2002 were obtained from the FAOSTAT database. Five-year means for energy, total fat, MUFA, PUFA, SFA and 'other fat' per capita were calculated, with their standard deviations, for each country. Bivariate correlations and a multiple linear regression model were used to test for the association between prevalence of obesity and types of fat available in these countries.

Results: Not surprisingly, dietary energy supply, SFA, PUFA and 'other fat' were positively associated with the prevalence of obesity. We also found, however, a strong negative association between MUFA availability and obesity prevalence (beta= -0.68, P<0.0001).

Conclusion: Populations with a lower prevalence of obesity seem to consume a greater amount of MUFA. Considering the partial correlations between variables, our results suggest that in countries with higher obesity prevalence, it is the shift from MUFA to PUFA that particularly appears to be associated with the risk of obesity.