instead of going to the local diner with the rest of the office team. Studying this population will
increase our understanding of ways to address this social health problem.
Two recent systematic literature reviews of weight loss programs called for three
advancements to further our knowledge (Nothwehr; 2004; Tsai & Wadden, 2005). First, the
authors asked for an agenda assessing modifiable weight loss variables (e.g., self-efficacy) rather
than relatively fixed variables that could not be altered within a program (e.g., genotype, gender,
ethnicity, age). Second, the authors challenged researchers to organize their efforts under a
unified framework (Tsai & Wadden, 2005; Nothwehr, 2004). Third, the authors challenged
researchers to develop more sophisticated research investigation designs.
This research is designed to address these three concerns. In this paper we will propose a
model testing the modifiable variables, use a quasi-experimental design to assess the model, and
collect data through field research of three different groups of people currently trying to lose
weight through diet and exercise. We begin by reviewing the literature on the modifiable
variables of concern in current weight loss programs
Diet Adherence
People start weight reduction programs daily. While understanding the factors that
motivate people to begin an exercise and/or diet program is important, this investigation focuses
on people who already are part of a diet program. Adherence is the extent to which a person
continues the decided mode of treatment or intervention as prescribed whether pursuing a
program on their own or partaking in a commercial or medically-supervised program. We
propose that outcome expectations, self-efficacy, past behavior, vicarious experience, and social
support directly or indirectly affect adherence to diet and level of physical activity
1
Physical activity is defined by Bouchard and Shephard (1994) as “any body of movement provided by skeletal
muscles that results in a substantial increase over the resting energy expenditure.” Under this broad rubric active
physical leisure, exercise, sport, occupational work and chores are all considered and tested. In the survey (see
Appendix A) the word exercise is used because the initial focus group preferred to read the word “exercise” over the
phrase “physical activity.” The questions did test the broader rubric as defined by physical activity.
Convention