Aim of the study:
In the present study, we aimed to examine the construct validity of the Three-Factor Eating Questionnaire-R18 (TFEQ-R18) and to investigate variables of the following phenomena such as cognitive restraint, uncontrolled eating and emotional eating in normal weight women and women with obesity.

Subject or material and methods:
The research sample comprised 237 participants (200 with normal weight and 37 obese): the Three-Factor Eating Questionnaire-R18 was distributed to all participants at the same time.

Results:
We have found that the three-factor structure is invariant at each level— configural, metric, scalar, and strict. Individuals with obesity scored significantly higher than individuals within normal weight range in uncontrolled eating (p = .005) and emotional eating (p = .053).

Discussion:
Observed ambiguities between the results provided by the current and other studies may be explained in terms of the controlling of the shared variance and measurement error, since only up to date summarized scores were compared across groups.

Conclusions:
These results broaden knowledge of eating behaviours in normal weight individuals as well as those with obesity.