Weight Tracking and Weight Loss Outcomes: Establishing the Standard of Care

Age, sex, marital status, employment status, income level (categorical), race, and ethnicity will be assessed by self-report at baseline

Self-monitoring data on diet, physical activity, and weight from electronic or paper records will be recorded by interventionists at each session by compiling printouts of electronic records from websites supported by electronic monitoring tools, and by photocopying paper diaries for participants without electronic monitoring tools.

Participants complete an 8-item questionnaire to assess beliefs about their weight tracking assignment during the study. The measure asks participants to rate daily, weekly, or no weight tracking in terms of ease, interest level, ability to remember, awareness, reward value, usefulness, understanding, and how motivated they are to engage in their assigned weight tracking frequency. These items measure aspects of cue strength and motivational value, both of which are important to the process of behavior modification within a social-ecological frame (DiClemente et al., 2001; Elder et al., 2007)

To elucidate factors that may impede engagement in daily or weekly weight tracking, participants will complete an assessment of perceived barriers to tracking weight. Items for this measure were adapted from a measure of barriers to diet and exercise developed by a member of the research team and used in numerous weight loss studies These items will provide feedback on factors that may interfere with weight tracking and will provide guidance for adaptation and use of weight tracking instructions for future interventions.

Self-efficacy for dietary intake, physical activity, and weight tracking behaviors will be assessed using a 15-item scale developed by members of the research team (Linde et al., 2006).

Participants will complete brief screening items developed for the study to assess smoking status, sedentary behavior (television viewing) and days per week of engaging in weight control behaviors, including diet and physical activity monitoring. Weight tracking frequency (never, every other month, monthly, weekly, or daily) and number of body weight scales at home will also be assessed.

The Diet History Questionnaire (DHQ, 2010) is a food frequency questionnaire (FFQ) that assesses usual intake and portion size of 124 foods. Responses are scored and analyzed using proprietary Diet*Calc software, which provides reasonable and valid estimates of macronutrient and caloric intake compared to 24-hour recall administrations (Millen et al., 2006) and alternate FFQ protocols (Subar et al., 2001). A subset of 168 participants (50%; 56 per treatment condition) will be randomized at baseline to a 24-hr dietary recall protocol.

The Paffenbarger Activity Questionnaire (PAQ; Paffenbarger et al., 1978) will be administered to provide an estimate of calories expended per week in leisure time physical activities. The PAQ has been associated with weight loss outcomes in intervention trials (e.g., Harris et al., 1994). A subset of 168 participants (50%; 56 per treatment condition) will be randomized to a 7-day accelerometer protocol at baseline and 12 months to enhance physical activity measurement during active weight loss, to elucidate any changes in daily patterning of activity that might occur during intervention.

The Appearance Evaluation subscale of the Multidimensional Body-Self-Relations Questionnaire will assess body image.

The Rosenberg Self-Esteem Scale (Rosenberg, 1979) will rate global self-esteem and will be used to track well-being during the study.

The Beck Depression Inventory (BDI-II) will assess depressive symptoms that may change over the course of the study period.

The Beck Anxiety Inventory (BAI) will assess anxiety symptoms that may change over the study.

The Positive and Negative Affect Schedule - Expanded Form (PANAS-X) will be administered as a momentary assessment of mood during randomly selected intervention sessions. The measure, consisting of 60 adjectives that are rated on a five-point Likert scale (from 1=very slightly or not at all to 5=extremely), assesses positive and negative affect, basic negative emotions (fear, hostility, guilt, sadness), basic positive emotions (joviality, self-assurance, attentiveness), and additional mood states (shyness, fatigue, serenity, surprise).

The Life Experiences Survey (Sarason et al., 1978) will assess a broad range of life changes and events that could affect participation in weight tracking or other study recommendations. We expect that participants who endorse a greater number of stressful life events will have poorer adherence, will be less able to maintain tracking diaries, and will experience greater negative affect relative to those with fewer life events during the study (Dunkley et al., 2003; Sarason et al., 1978).

Measures used to screen participants prior to study entry will be repeated during the trial for ongoing monitoring. These include the Questionnaire on Eating and Weight Patterns to assess binge eating, and the SCOFF Eating Disorder Screening Questionnaire to assess presence of symptoms associated with anorexia or bulimia.