To provide an in-depth analysis of the relationship between obesity and fast-food consumption by comparing urban obese and normal-weight Saudi Arabian children.

A multicentre cross-sectional study was conducted from December 2015 to March 2016. Participants were divided into two groups (normal weight and obese) and further stratified by sex. Groups were randomly selected using a multistage stratified cluster-sampling technique. A self-paced questionnaire was used to collect data relating to food consumption. Weight height and waist circumference were measured and bioelectrical impedance analysis was performed in all children.

Capital of Saudi Arabia, Riyadh.

Children aged 9·00–11·99 years (n 1023).

Compared with normal-weight groups, intake frequency of fast food/week was higher among the obese groups (P<0·001), irrespective of fast-food consumption outside (P<0·001) or inside (P<0·001) the home; and larger portion sizes were preferred in obese groups (P<0·001). Families eating fast-food meals together was a protective factor against obesity (OR; 95 % CI: 2·67; 1·44, 4·96, P<0·001), with similar results for families ordering from a ‘healthy meals menu’ for their children (1·90; 1·24, 2·90, P=0·002). Taste of fast foods (P=0·021), child-friendly menu (P=0·020) and meal cost (P<0·001) were identified as main reasons why parents took their children to fast-food restaurants; these data were replicated for parents with obese boys, but not girls.

Development of effective interventions to reduce fast-food consumption in Saudi Arabian schoolchildren requires greater research-based evidence of fast-food consumption habits and practices associated with increased childhood obesity.