Abstract Introduction: This pilot study will determine the recruitment feasibility, retention, and adhesion for a motivational interviewing program for weight loss in adults according to the processes of change in weight loss.

Methods and Analysis: The single-arm pilot study will be a feasibility study of the Motivation to Lose Weight version 1 (MLW v.1). The study includes presential and online sessions. Participants will be recruited through advertisements on social media and selected according to the inclusion criteria. Participants will receive 8 sessions of approximately 30-45 minutes of motivational interviewing (MI) according to the processes of change in weight loss, as measured by the S-Weight scale. The results will be evaluated at the beginning and the end of the program, which will last 8 weeks. The primary outcome of the study is feasibility. The intervention will be feasible if adherence to the proposed activities in the sessions is greater than 70%, we can recruit 10 patients within 8 weeks, the proportion of interested people and registered participants is greater than 30%, and more than 75% of participants attend the final study visit. The secondary outcome is weight loss, fat mass percentage, muscle mass, waist and hip measurements, and the scores of behavioral scales.

Ethics and discussion: The feasibility of this project consists of proposing an individualized intervention based on MI strategy(s) for each participant, according to the stage of readiness, and thus, help to evolve in the process of losing weight. This intervention aims to increase the participant's confidence level to implement actions that lead to the progression of behavior and, consequently, the action and maintenance of the lost weight. This study was approved by the Research Ethics Committee (REC) of the Hospital de Clínicas de Porto Alegre (HCPA) under number 20220209 CAAE 59573622300005327.

The study will consist of one session per week for 8 weeks, during which the participant will receive MI for 30-45 minutes. All participants will receive the MI intervention according to their readiness to lose weight measured by means the P-weight and S-weight at the beginning of each session.

In session one, sociodemographic and clinical information will be collected through a structured interview as well clinical assessment including the following scales: the stage of change to lose weight (S-Weight), symptoms of depression (PROMIS depression v. 8.1a, ), anxiety (PROMIS anxiety v.8.1a, ), psychosocial functioning (FAST ), binge eating (TCAP ), current food intake (24-hours food recall, ), and cognitive process used while losing weight (P-Weight ). In addition, the first session will collect information regarding the participant's body weight, body fat, free fat mass, and waist and hip circumference.

As participants will be in the precontemplation or contemplation stage of change at the beginning of the study, the goals of the first session will be: a) develop participant rapport; b) develop the discrepancy, that is, understand the distance between what the participant wants to change and the actions are taken; c) roll with resistance, that is, do not conflict during the dialogue; d) avoid the correction reflex, that is, avoid correcting something the interviewee says, even if it is technically incorrect or not plausible; e) valuing and validating the person, that is, emphasizing points in the participant's speech to increase their self-confidence; f) establish an agenda of issues to be deal with that are related to being overweight or obese. All these objectives remain in subsequent sessions. To accomplish those goals, the interviewer will use the MI process called "explore," which leads to the topic the participant wants to discuss. The interviewer will use strategies such as open questions, affirmations, reflections, abstracts, exploring discrepancies, informing with permission, explore values and objectives based on the participants' speech in order to elicit from the person their different motives for the desired change . Each session will be registered following the Session Registration Form .

From sessions two to seven, the sessions will take place online through the platform Teams, and the participant will answer the S-weight scale to identify the actual stage of change to lose weight at the beginning of each session. In case of the participant is in the precontemplation, contemplation or preparation phases, the goals in the session will be a) encourage the participant to talk about the reasons that favor him to change and not to change; b) focus on the positive motives to change; c) Increase the participants' confidence, that is, explain that the style of this approach takes into account their autonomy, and thus, any and all decision-making will be shared and not directed from the interviewer to he/she, also because a basic premise of MI is that people are experts on themselves; d) extract from the participant how he/she could make the change, anticipating what it would be like if he/she had already made the change; e) show options for the participant to choose from, based on their own answers; f) stimulate through questions and reflections that the participant himself talks about his/her abilities, this increases the confidence that he is capable of doing things; g) prepare the participant for the action phase; h) predict difficulties; and i) prevent relapse. However, if the participant is in the action, maintenance, or relapse phase, the goals will be to a) stimulate the participant to develop solutions to promote autonomy and confidence in the decision-making process; b) reinforce the commitment to change; c) recall the participants' values through reflections; d) validate the actions already taken, even if they are damage reductions; e) support self-confidence; f) increase support network; g) prevent relapse; and h) consolidate the gains from the changes made.

The goals established in sessions two to seven will be pursued by the interviewer by using the MI process "focus," "evoke," and "plan". Focus will direct the conversation toward the possibility of change, creating a discrepancy between the participants' current actions and their broader life goals and values . Evoking will stimulate the participant to talk about their motivations for change. Planning includes helping the participant to identify a goal, building an action plan, and anticipating difficulties. The interviewer will use strategies such as closed questions, open questions, reflection, importance rule, and trust ruler.

In the last session, the participant will attend an in-person session for the measurement of body weight, body fat, free fat mass, waist, and hip circumference, as well as the assessment of the same clinical scales used in the first session). In addition, the participant will fill in a questionnaire regarding the interviewer's attitude during the sessions, which will indicate the compliance of the researcher with the MI approach.

Inclusion Criteria:

Aged 18-60; BMI from 25-34.90 (Kg/m²); Residents of Porto Alegre and nearby regions; No weight loss treatment in the last 6 months; Pre-contemplation or contemplation phase for changing body weight when responding to the S-Weight scale; Stable body weight in the last 3 months (<2% loss); Access to Teams platform; Have access to a body weight scale.

Exclusion Criteria:

Major surgery in the last 3 months; Diagnosed eating disorder; Use of mood stabilizer drugs or antipsychotics, antiobesity or adjuvants in weight control, as well as corticoids (prednisone and similar) in doses greater than 10 mg per day; Dietary treatment for weight loss in the last 6 months; Myocardial infarction or angioplasty in the last 3 months, with chronic kidney disease or undergoing dialysis; with chronic liver failure (Ascites), with congestive heart failure, undergoing treatment for cancer or with the Human Immunodeficiency Virus (HIV); Pregnant and lactating women.

people over 18 and under 60