Introduction: to analyze the association between frequency of food consumption and presence of overweight / obesity using data from the Spanish National Health Survey 2006 (NHS-06).

Material and Methods: retrospective cross-sectional study of secondary sources of NHS-06. To selected 29.321 subjects answered the food frequency questionnaire, consist of a list of 12 groups that asked about their frequency of consumption in 5 response options and to categorized into three for analysis (daily, weekly and occasional). Descriptive analysis of the consumption of food groups categorized by frequency of consumption, and calculating the difference (gap) between men and women. The association between food consumption frequency with overweight-obesity was performed using logistic regression.

Results: 40.7% of the population consume vegetables daily and 65.2% consume fruit daily. 69.8%, and 46.3% of women complies with the recommendations for fruit consumption (gap -7.2), and vegetables (-14.0 gap) respectively. Eating fruit occasionally, decreases the probability of obesity (OR = 0.72 95% CI 0.63 to 0.82), opposite to consume daily. Eating sausages daily, reduces the probability of obesity (OR = 0.75 95% CI 0.68 to 0.83), compared to occasional use.

Conclusions: the results show scientific contradictions by the presence of bias in the instrument used in the collection of information. Suggesting the need, that the NHS includes a method for collecting dietary and nutritional information validated and adopted, allowing higher quality measurements.