Resumen: Obesity is a major health problem associated with disease burden and mortality. In this context, analyzing food as a powerful reinforcer from a behavioral economics framework could be relevant for the treatment and prevention of obesity. The purposes of this study were to validate a food purchase task (FPT) in a clinical sample of Spanish smokers with overweight and obesity and to assess the internal structure of the FPT. We also analyzed the clinical utility of single-item breakpoint (i.e., commodity price that suppresses demand). A total of 120 smokers [% females: 54.2; Mage = 52.54; SD = 10.34] with overweight and obesity completed the FPT and weight/eating-related variables. Principal component analysis was used to examine the FPT structure, and a set of correlations were used to examine the relationship between the FPT, eating and weight-related variables. The FPT demonstrated robust convergent validity with other measures of eating. Higher food demand was related to higher food craving (r = .33), more binge eating problems (r = .39), more weight gain concerns (r = .35), higher frequency of both controlled (r = .37) and uncontrolled (r = .30) grazing, as well as to an eating style in response to emotions (r = .34) and external eating (r = .34). Of the demand indices, Intensity and Omax showed the highest magnitudes of effects. The FPT factors, persistence and amplitude, do not improve individual FPT indices; and the single-item breakpoint was not related to any eating or weight variable. The FPT is a valid measure of food reinforcement with potential clinical utility in smokers with obesity/overweight. Idioma: Inglés DOI: 10.1016/j.appet.2023.106549 Año: 2023 Publicado en: Appetite 185 (2023), 106549 [7 pp.] ISSN: 0195-6663 Factor impacto JCR: 4.6 (2023) Categ. JCR: NUTRITION & DIETETICS rank: 21 / 114 = 0.184 (2023) - Q1 - T1 Categ. JCR: BEHAVIORAL SCIENCES rank: 7 / 55 = 0.127 (2023) - Q1 - T1 Factor impacto CITESCORE: 9.1 - Nutrition and Dietetics (Q1) - Psychology (all) (Q1)