A Polish adaptation and validation of  the  Yale Food Addiction Scale 2.0

Introduction
Food addiction is defined by a pattern of eating high-calorie foods, which is similar to psychoactive substance dependence. The aim of the study was to validate the Polish adaptation of the Yale Food Addiction Scale 2.0 (YFAS 2.0), which measures the degree of food addiction based on 11 addiction criteria according to DSM-5.

Material and methods
Validation studies were carried out on a sample of 431 people (67.75% women), aged 18-60. Construct validity was assessed using CFA (confirmatory factor analysis) for dichotomous diagnostic data. Reliability was assessed by analysing time stability of the results, internal consistency and item-total correlations. Validity was assessed using body weight, BMI, Scale of Involvement on Eating Behaviour (SZJ), Three Factor Eating Questionnaire and Self-Control Scale. Differences in selected reliability indicators depending on the YFAS 2.0 diagnostic grades were analysed. The severity of symptoms was compared between food addicts anonymous, individuals enrolled in a weight-loss programme and those from a normative sample.

Results
CFA demonstrated a perfect fit between the study results and the theoretical model of the YFAS 2.0. High coefficients of reliability measures were obtained. The YFAS 2.0 positively correlates with body weight, BMI, SZJ results, difficulties in controlling eating and emotional eating, and negatively with self-control ability. Significant differences were found in the validity indicators and between compared groups, depending on the diagnostic degrees of food addiction. Discussion: The Polish adaptation of YFAS 2.0 is characterised by high reliability and validity.

Conclusions
The Polish adaptation of YFAS 2.0 has very good psychometric properties and can be used in scientific research and clinical practice.