The present study showed that the health education program based on the theory of planned behavior is effective in encouraging pre-diabetic women to promote a healthy lifestyle and improve their fasting blood sugar.
In this study drop outs of samples during study because in the process of creating health behaviors in order to change women attitudes and create stability and sustainability in health behaviors (diet and physical activity), intervention with adequate time in educational sessions are needed therefore drop outs of samples during study. However, to improve some educational content can be delivered indirectly by means of educational booklets, pamphlets, or via social media to reduce the number of training sessions.
In this study, results of the baseline assessment showed that the pre-diabetic women information about healthy life style was 0.059 of 1 score. After three sessions of face-to-face training, the knowledge of pre-diabetic women in the experimental group increased significantly (0.73 of 1 score) in comparison with before the intervention and the control group, which is consistent with the results of the study of Blanks . During the sessions, people were informed about behaviors that reduce the risk of diabetes, and given the role of women in preparing and cooking food, improving knowledge can significantly affect the quality of their family nutrition. After the educational intervention, the attitude related to physical activity in the intervention group increased significantly, which was consistent with the results of the study of Sanaeinasab , White  who had studied physical activity using the theory of planned-behavior. However, in the present study, in line with White’s study , no significant increase was found in the attitude of the intervention group regarding a healthy diet. However, the control group’s attitude in this regard increased significantly. Completing a questionnaire in this group can affect their belief in the importance of eating healthy food and improve their attitude.
After the intervention, no significant change was found in the subjective norm of the experimental group in relation to physical activity and healthy diet, which contradicts the Maleki’s study . Also in Taghipour’s study , holding training sessions on physical activity for the family and friends of the volunteers, led to the promotion of subjective norms related to physical activity in the intervention group. In the present study, the intervention group was asked to provide an educational booklet to their family members, which we assumed would affect their subjective norms. Therefore, it can be concluded that this method of intervention is unsuccessful in improving the subjective norms of the participants and other methods should be used to improve the subjective norms.
After the educational intervention, the mean score of perceived behavioral control in the experimental group increased, which indicates an increase in the ability of individuals to withstand barriers to physical activity and is consistent with the findings of Sanaeinasab .
The literature on people with pre-diabetes shows those participating in self-management and self-efficacy training progress along the continuum necessary for making and sustaining behavior change [19,20,21].
In the present study, presenting an educational program on factors facilitating the behaviors, providing incentives, reducing and eliminating the perceived barriers, and using the experiences of participant increased the women perceived behavioral control in the intervention group. However, no significant change was found in the perceived behavior control about healthy life style diet in the intervention group. Therefore, it can be concluded that improving healthy diet need to longer an educational session or other methods should be used to improve the perceived behavior control about healthy diet.
Findings show that there was not statically significant difference between before and after intervention in terms of diet in the intervention group because almost TPB construct (attitude, perceived behavior control, intention and knowledge) low increased after intervention.
In the educational intervention, in addition to expressing the benefits of exercise and the harms of inactivity, strategies for adopting sports behaviors and a list of physical activities that can easily be done daily were presented and participants were encouraged to select activities that they could do regularly. However, no significant change was found in the behavioral intention of the intervention group and the average physical activity performance of both groups decreased (although it was not statistically significant), which was consistent with the result of the study of Williams et al.  on Physical activity of outpatients using TPB. While Sanaeinasab  showed that TPB is effective in promoting physical activity, the reason for this discrepancy could be the cold weather conditions and the global outbreak of coronavirus during the follow-up period in the present study.
Consistent with the study by Chen et al.  that a 16-week empowerment program in three phases including awareness, behavior development, and ABC outcomes for pre-diabetic patients significantly improved healthy lifestyles and self-efficacy, in the present study the mean dietary performance in pre-diabetic women in the intervention group was also significantly higher than the control group. After the educational intervention in the experimental group, the mean fasting blood sugar improved in comparison with before the intervention and the control group, which is in line with the study of Shamizadeh  using social cognitive theory, Chen’s  using ABC empowerment program and Ibrahim’s  using a community-based healthy lifestyle intervention program.
The improvement in fasting blood sugar of the experimental group in our study could be due to the improvement in dietary performance in the experimental group. After the intervention, no new cases of diabetes were observed among pre-diabetic patients in the intervention group.
One of the strengths of the present study is investigating the unknown group of pre-diabetics who are difficult to access and at high risk for diabetes. Moreover these finding results can be used by others in the world especially in developing countries (with similar socio-economic status) because theory-based training in the present study can be promotion knowledge and healthy lifestyle in pre-diabetics women.
Among the limitations of the present study are the collection of information by self-report, follow-up of samples, coincided with the prevalence and critical conditions of the coronavirus, and also the lack of predisposing cases in the electronic health record, has made it difficult to identify these people.
It is suggested that future studies should be conducted with other theories and questionnaires with more specific questions about healthy lifestyle behavior and asses the glycemic control with glycosylated hemoglobin test.