This thesis study is designed to examine the effects of nutrition education provided to individuals with thyroid dysfunction on their quality of life and adaptation to the disease. The data will be collected using the Descriptive Characteristics Form, the Nutrition Attitude Scale, the Quality of Life Scale for Thyroid Patients (ThyPRO), and the Chronic Illness Adherence Scale. The Body Mass Index (BMI) of participating patients will be calculated by the researcher based on measured height and weight. Laboratory values including TSH, free T4, and free T3 will be obtained from the patients' medical records on the day of assessment. Data collection will be conducted in two phases. The study population will consist of all patients diagnosed with thyroid dysfunction who present to Dr. Burhan Nalbantoğlu Hospital. Using the G*Power 3.1.9.2 software, the required sample size was calculated prior to data collection with a 95% confidence level. For correlation analysis, an alpha value of 0.05, an effect size of 0.455, and a statistical power of 95% were assumed, resulting in a minimum sample size of 56 participants (30 per group). Accounting for potential data loss, a total of 60 patients (30 per group) are planned to be included in the sample.

This thesis study is designed to examine the effects of nutrition education provided to individuals with thyroid dysfunction on their quality of life and adaptation to the disease. Patients with thyroid disorders are affected both physically and socially due to hormonal imbalances. In this context, the study aims to investigate how dietary habits are shaped and how these habits influence individuals' overall quality of life. Accordingly, the following research questions were addressed:

• Does the nutrition education provided affect the level of nutritional knowledge in patients with thyroid dysfunction?
• Does the nutrition education provided improve the quality of life in patients with thyroid dysfunction?
• Does the nutrition education provided enhance disease adaptation in patients with thyroid dysfunction? Implementation of the Study Prior to the nutrition education, patients will be informed about the purpose of the study, the data collection methods, and the content of the educational topics. Patients who agree to participate in the study will be asked to sign an informed consent form. The Body Mass Index (BMI) of participating patients will be calculated by the researcher based on measured height and weight. Laboratory values including TSH, free T4, and free T3 will be obtained from the patients' medical records on the day of assessment. Data collection will be conducted in two phases.

Phase 1:

All patients who agree to participate in the study (both intervention and control groups) will first be asked to complete the "Descriptive Characteristics Form," the "Nutrition Attitude Scale" to assess their dietary habits, the "ThyPRO Questionnaire" to evaluate thyroid-related quality of life, and the "Chronic Illness Adherence Scale (CIAS)" to assess disease adaptation.

The Body Mass Index (BMI) of each participant will be calculated by the researcher through direct measurement of height and weight. Free T4 and free T3 values will be obtained from the patients' medical records on the day of evaluation.

Participants in the intervention group, selected through randomization, will receive a one-on-one, face-to-face educational session in the outpatient clinic's education room. The session will be conducted by the researcher using a PowerPoint presentation titled "Nutrition Education for Thyroid Patients," prepared specifically for the study and delivered via computer. At the end of the session, participants will also be provided with a printed "Nutrition Guide for Thyroid Patients." Participants in the control group will not receive the educational session at this stage; however, they will be given the same printed "Nutrition Guide for Thyroid Patients" prepared by the researcher. It will be communicated to the control group that the same individual training session will be offered to them after the study concludes.

The education will be delivered as a single session, with an expected duration of approximately 30-35 minutes. Following the training, the "Nutrition Attitude Scale" will be re-administered to reassess participants' knowledge levels.

Phase 2:

Three months after the initial planned education session, participants will again complete the "Nutrition Attitude Scale" to assess changes in dietary habits, as well as the "ThyPRO Questionnaire" and the "Chronic Illness Adherence Scale (CIAS)" to evaluate changes in thyroid-related quality of life and disease adaptation. If available, free T4 and free T3 values will be obtained from hospital records on the day of follow-up, and BMI will be recalculated by the researcher.

Participants in the control group will also be asked to complete the same forms three months after the initial assessment. Following the completion of the data collection process, the same one-on-one education provided to the intervention group will be delivered to the control group to eliminate any disadvantage or ethical concerns.

Data Collection Tools:

The data will be collected using the Descriptive Characteristics Form, the Nutrition Attitude Scale, the Quality of Life Scale for Thyroid Patients (ThyPRO), and the Chronic Illness Adherence Scale.

The study population will consist of all patients diagnosed with thyroid dysfunction who present to Dr. Burhan Nalbantoğlu Hospital. Using the G*Power 3.1.9.2 software, the required sample size was calculated prior to data collection with a 95% confidence level. For correlation analysis, an alpha value of 0.05, an effect size of 0.455, and a statistical power of 95% were assumed, resulting in a minimum sample size of 56 participants (30 per group). Accounting for potential data loss, a total of 60 patients (30 per group) are planned to be included in the sample.

Data Analysis The data obtained in the study will be analyzed using SPSS software (Windows version 25.0). Descriptive statistical methods such as frequency, percentage, minimum-maximum values, median, mean, and standard deviation will be used for data evaluation. The normality of the data for the scales used will be assessed through tests of skewness and kurtosis. For normally distributed quantitative data, comparisons between two independent groups will be performed using the independent samples t-test, while comparisons among more than two groups will be conducted using one-way analysis of variance (ANOVA).

Inclusion Criteria:

• Not having any physical or mental disabilities
• Not having received such training before
• Volunteering to participate in the study
• Be 18 years of age or older.

Exclusion Criteria:

• Being under 18 years of age.
• Having cognitive dysfunction.
• Not volunteering to participate in the study.