## 3 Results  
The patient consistently achieved a reduction in anxiety levels by at least 40% or maintained levels equal to or less than 40% of the initial measurement throughout the sessions. Alongside these improvements in anxiety, the avatar's BMI progressively increased by 0.9 kg/m\({}^{2}\) each session. This gradual increase allowed the patient to progress through the entire hierarchy of avatar BMI values, ultimately reaching the target BMI of 18.36 (representing the 25 th percentile), as established by the treating physicians. For a detailed representation of the incremental changes in the avatar's BMI, refer to Table 2.  
Throughout the five treatment sessions, the actual BMI consistently ranged from 14.79 to 14.95. In the post-treatment session, an increase in BMI was observed, reaching 15.02. This upward trend continued in the follow-up session, where the patient successfully achieved the target healthy BMI of 18.79, slightly surpassing the 25 th percentile BMI of 18.36 initially set by the clinicians overseeing the treatment. As depicted in Figure 3, the patient initially exhibited a high level of fear of gaining weight, which markedly decreased by the end of the treatment, achieving very low values at both the post-treatment assessment and the follow-up. Anxiety levels, initially medium to high during the first two sessions, progressively decreased from the third session onward, reaching very low levels by the post-treatment assessment, and they were completely eradicated by the follow-up. Levels of FBOI were moderate initially but gradually increased, reaching a high level at both the post-treatment assessment and the follow-up. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Session** & **BMI Increase** & **Avatar’s** & **Patient’s Actual** \\  & & **BMI** & **BMI** \\ \hline Pre-treatment session & No increase & 14.40 & 14.40 \\
1\({}^{\circ}\) VR session & No increase & 14.79 & 14.79 \\
2\({}^{\circ}\) VR session & Increase of 0.9 point & 15.68 & 14.79 \\
3\({}^{\circ}\) VR session & Increase of 0.9 point & 16.57 & 14.83 \\
4\({}^{\circ}\) VR session & Increase of 0.9 point & 17.46 & 14.79 \\
5\({}^{\circ}\) VR session & Increase of 0.9 point & 18.36 & 14.95 \\ Post-treatment session & No increase & 15.02 & 15.02 \\ Follow-up session & No increase & 18.79 & 18.79 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The body mass index (BMI) values of the avatar in the five virtual reality sessions and the BMI values of the patient during these sessions. Figure 3: (**a**–**c**). Scores from the VAS measuring fear of weight gain (**a**), anxiety (**b**), and FBOI (**c**) across eight sessions. ’Pre’ refers to the pre-treatment assessment session; ’I’ to ’V’ denotes the first through fifth treatment sessions, respectively; ’Post’ indicates the post-treatment assessment session; and ’Follow-up’ refers to the follow-up assessment session. The patient showed a statistically reliable reduction in body dissatisfaction, drive for thinness, body anxiety, and body-checking behavior following treatment. These improvements were further enhanced after a six-month follow-up, maintaining a significant and reliable reduction. Additionally, there was a considerable and reliable improvement in measures of body appreciation, which continued to increase after 6 months. Regarding AB, initial scores for complete fixation time measures during pre-treatment assessment indicated the patient's avoidance of weight-related body parts. Following the intervention, the difference in complete fixation time between weight-related and non-weight-related areas of interest approached zero, indicating more balanced attention between these two types of body parts. After six months, there was a slight increase in the negative complete fixation time value, suggesting a partial resurgence of attentional avoidance of weight-related body parts, albeit less pronounced than in the pre-treatment session.