*2.1. Participants & Procedure*

Female patients with EDs, healthy controls, and individuals with obesity (from ages 18 to 65) were sampled out of three different data collections.

The sample of ED inpatients consisted of 286 patients, of whom 126 (44.06%) were diagnosed as AN-R, 69 (24.12%) as AN-BP, and 91 (31.82%) as BN through a clinical interview, and cross-validated by the eating disorder evaluation scale (EDES) [50]. The mean age and BMI of all ED subtypes are displayed in Table 1. The three ED subtypes did not differ significantly in age and were significantly younger than healthy controls and patients with obesity. Concerning BMI, AN patients (AN-R/AN-BP) had a significantly lower BMI than BN patients and healthy controls (normal weight) and Class II/III obese patients (severe overweight). All data were collected at the admission of these patients at a specialized inpatient treatment unit for EDs in Flanders, the Dutch-speaking part of Belgium.

The sample of female patients with Class II/III obesity was collected during an intake for a bariatric surgery trajectory at a general hospital in the Dutch-speaking part of Belgium. The presence or absence of binge eating was determined by two items (overeating + loss of control) of the Dutch version of the eating disorder examination questionnaire (EDEQ; see Section 2.2. Instruments). About 210 patients were diagnosed with Class II obesity, of whom 72 (34.29%) engaged in binge eating, and 430 patients with Class III obesity, of whom 141 (32.79%) engaged in binge eating. These comorbidity rates of binge eating are in line with prior research [6]. The mean age and BMI of the individuals with Class II/III obesity with and without binge eating are displayed in Table 1. All patients with obesity were significantly older than patients with ED, and were similar in age to healthy controls (except patients of Class II obesity without BED, who were significantly older). Within the obesity subtypes (Class II and Class III), patients with binge eating were significantly younger than those without binge eating. Concerning BMI, obese patients had significantly higher BMIs compared to patients with AN (underweight), and BN and healthy controls (normal weight). Obesity Class III patients also had a significantly higher BMI than patients with Class II obesity.

Finally, the 126 healthy controls were collected from the Flemish-speaking general population of Belgium, taking into account the distribution of the Flemish population's age, gender, and education. The mean age and BMI of the healthy controls are shown in Table 1. Healthy controls were significantly older than patients with an ED, and similar in age to patients with obesity (except patients of Class II obesity without binge eating, who were older). Concerning BMI, healthy controls had a normal BMI, as did BN patients. However, their BMI was higher than patients with AN, and lower than patients with Class II/III obesity.

All patients and healthy controls gave their informed consent to use their data anonymously for research purposes. The three data collections from which the data were pooled were approved by the ethical committee of the Faculty of Psychology and Educational Sciences (healthy controls) and/or the medical ethical committee of the medical institute in which the patients (with Eds and/or obesity) were treated. Given that the groups did significantly differ regarding age, this variable was included as a confounding variable in all analyses. Although groups also differed with respect to BMI, we did not include BMI as control variable, given that it is an essential characteristic of the diagnostic groups.



sensitivity); BAS = behavioral activation scale (reward sensitivity); TOT = total scale; DR = drive; FS = fun seeking; RR = reward sensitivity; EC = effortful control; INH = inhibitory control;

ACT = activation control; ATT = attentional control. \*\*\* *p* < 0.001, \*\* *p* < 0.01.
