The prevalence of overweight and obesity has risen dramatically among North American children and adolescents over the past 30 years [
1]. Although the etiology of obesity remains a topic of great debate, evidence clearly shows that obesity is associated with serious, physiological and psychological consequences. Physical consequences related to obesity include type 2 diabetes, hypertension, hyperlipidemia, insulin resistance, asthma, sleep-apnea, and increased likelihood of mortality [
2,
3]. Moreover, it has be shown that by age 10, 60% of overweight children have at least one biochemical or clinical cardiovascular risk factor and 25% have more than two [
4]. Even more alarming are future projections which indicate that if current trends continue, one third of the children born in the year 2000 will eventually develop type 2 diabetes [
5]. In addition to the physiological outcomes associated with being overweight or obese, these children are also likely to experience severe psychological and emotional problems as a result of the harmful social stigma and ridicule. Specifically, research has shown that these children are stereotyped as unhealthy, academically unsuccessful, socially inept, unhygienic, and lazy [
6]. Furthermore, overweight and obese youth are more likely to be the victims of verbal, physical, and relational bullying, and they experience more teasing and peer rejection than do their normal-weight peers [
7]. The aforementioned social problems are predictive of both short and long-term psychological consequences, including: body dissatisfaction, low self-esteem, poorer health-related quality of life and higher rates of depression [
8,
9].
Traditional Psychological Interventions for Weight-Loss
Improving childhood weight status and health outcomes will require concerted effort at multiple levels of intervention and counseling by health care professionals represents an important component of the public health response [
10]. Cognitive-behavioral treatment has been found to effect positive behavior changes for weight-loss [
11]. This psychological method of treatment is based on the theory that the problem in question (eg, obesity) is maintained by specific dysfunctional cognitions and beliefs. The CBT therapist therefore attempts to modify behaviors using techniques designed to identify, evaluate, and then restructure related maladaptive cognitions and beliefs [
11].
Despite the benefits of CBT, there are limitations to this approach, which have implications for a client's adherence to a prescribed health behavior program. For instance, CBT can be a direct approach whereby clients' beliefs are challenged and they are directed to explore the evidence that counters their present schema. This method may therefore not be as effective if clients are not ready to recognize maladaptive belief patterns (i.e., they are in a pre-contemplative stage of change). As well, CBT is not designed to engender intrinsic motivation to make necessary changes, again which can have implications for program adherence. Adherence to a weight-loss treatment protocol, such as consuming the recommended amount of calories, becomes a critical component of success. In fact, continued adherence to the prescribed diet has been found to be essential to weight loss success, regardless of the type of diet [
12]. Taken together, research suggests that CBT shows a mixture of results [
13] and can fall short in some important areas. Thus, alternate treatments of obesity are needed, and particular attention needs to be paid to interventions that speak to the issue of readiness to change and motivation to maintain program adherence.
Motivational Interviewing as an Intervention for Weight-Loss
One empirically supported intervention with a large evidentiary base for improving adult outcomes in behavioral health-related disorders is Motivational Interviewing (MI). MI is strongly rooted in the client-centered therapy of Rogers [
14]. Its relational stance emphasizes the importance of understanding the client's internal frame of reference and displaying unconditional positive regard for the client. MI can thus be defined as a client-centered, directive method of therapy for enhancing intrinsic motivation to change by exploring and resolving ambivalence [
15]. MI manifests through specific strategies, such as reflective listening, summarization, shared decision making, and agenda setting. A notable feature of this approach is the importance of the therapist's empathic attunement to emergent client concerns and the communication of accurate understanding. The therapist's capacity to embody the MI spirit and establish a secure empathic bond with a client is thought to be central towards achieving positive treatment outcomes [
16].
In addition to empathic responsivity, MI also has a directive component which specifies goals of reducing ambivalence and increasing a client's own intrinsic motivation to change without countering an individual's previously held beliefs. In fact, an MI therapist typically makes no direct attempt to confront denial, dismantal irrational or maladaptive beliefs, or persuade. Confrontation with a client's personal beliefs can damage the therapeutic rapport and build defensiveness rather than confidence. Instead, the therapist helps the client think about and verbally express their own reasons for and against change and how their current behavior or health status affects their ability to achieve their life goals or fulfill core values [
17]. Thus MI has proven to be a valuable tool for eliciting intrinsic motivation to make changes by encouraging clients to find their own means and their own solutions [
18].
Why does MI Work? Intrinsic Factors Related to Behavior Change
When attempting to explain the intrinsic factors essential to MI, it is helpful to first consider a theoretical model of behavior change. Prochaska's transtheoretical model of change, for instance, breaks down the concept of readiness to change into stages from pre-contemplation (i.e., not at all contemplating change) to contemplation, action and maintenance of the behavior change once it is made [
19]. This model emphasizes the progression of behavior change through stages on a temporal dimension. That individuals are not uniformly in one stage of change, but rather tend to move back and forth fluidly between stages, is an important consideration of the behavior change model [
20].
Motivational interviewing is an evocative technique that may be used to facilitate progression through the stages of change. It is based on the assumption that an individual's readiness to change is variable and dynamic, and that different therapeutic techniques will be more constructive depending on their readiness for change. MI is thought to be particularly useful for people who are in the early stages of change as it is in these stages that individuals' consciousness about particular behavior is raised. Over time, MI helps individuals move from being unaware or unwilling to do anything about the problem to considering the possibility of change, to becoming determined and prepared to make the change [
21]. Furthermore, most behavior change models include the idea that there are at least two driving components to readiness to change: conviction/importance and confidence/self-efficacy [
15]. 'Importance' relates to why change is needed or what is driving the individual's desire to make a change, while 'confidence,' relates to the person's belief in their own ability to master change. Motivational Interviewing works on
both of these dimensions by helping the client to articulate why it is important for them to change and by increasing self-efficacy so that they have confidence to do so [
21].
Previous MI Intervention Studies
According to Rollnick, Miller and Butler [
22], support for the process of change as facilitated by MI has been demonstrated in many studies focusing on adult behavior changes, including drug and alcohol addiction, gambling and adherence to exercise and dietary modification. As such, while the behavior target can differ, the structure of the change process appears to be the same and the fundamental spirit of MI is revered. Using MI to effect weight-loss has been gaining more attention in recent years [
22]. Research has demonstrated that MI, in conjunction with standard treatment/treatment as usual (diet and exercise), has resulted in increased success (increased weight loss) for clients enrolled in adult weight loss programs [
23]. Moreover, studies have found that adults who show increases in self-efficacy are more likely to adhere to dietary programs and are thus more inclined to lose weight [
24]. However, the process by which MI effects change is lacking a model to explain the driving behavior mechanisms. As a result, the relationship between MI and self-efficacy is not well understood, particularly with youth.
Using Motivational Interviewing with children as a therapeutic technique for effecting behavior change is in the beginning stages [
17]. While there is some support for MI in adherence-related interventions involving youth (e.g., diabetes, asthma), the evidence base for the use of MI for overweight and obese youth remains limited [
25]. Two studies examined the effectiveness of using MI to effect changes in BMI. The "Go Girls" project [
26] divided adolescent girls ages 12-16 into high intensity (>20 behavioral intervention sessions) or a moderate intensity (≈6 sessions over the telephone) groups. No significant differences were found between groups at 6-month follow-up. The second study that was described, the "Healthy Lifestyles Pilot Study" looked at using MI with parents of overweight children ages 3-7. Parents in the low-intervention treatment group received one single session of MI, while the high-intensity group received two to four MI sessions [
27]. While decreases in BMI from baseline scores were demonstrated, significant differences between groups were not found.
The aforementioned MI studies raise many questions related to the methodological reliability and efficacy of using this therapeutic technique with pediatric samples. We will aim to address these knowledge gaps within the context of our ongoing cohort of obese and overweight youth. The specific purpose of this report is to present the methodology and design of the study investigating the efficacy of Motivational Interviewing on the impact of psychological and physiological wellbeing.