The rate of obesity is on the rise and continues to be a global concern and public health issue. Combining behavioural weight loss treatment with motivational interviews may increase weight loss in obese and overweight people.
Obesity rates continue to rise worldwide and according to one study, 65 million more adults in the USA are expected to become obese by the year 2030. The rising rate of obesity is of considerable concern mainly due to its association with chronic illnesses such as type 2 diabetes, hypertension, stroke, and heart disease. It is believed that obesity is a global pandemic that can be addressed through public health and behavioural interventions such as weight loss treatments.
Motivational Interviews and Weight-Loss Programs
In a recent study published in Trials, Moss and colleagues investigated the effect of administering motivational interviews (MI) in addition to behavioural weight-loss programs (BWLP) in obese and overweight adults. Behavioural weight-loss programs are usually considered first-line treatment in this patient population and consist of behavioural changes centred on increasing energy expenditure and decreasing energy intake. This regimen generally includes dietary modification, physical activity implementation, and behavioural self-management.
The researchers used motivational interviews to counsel and motivate participants into moving towards behavioural change. They hypothesized that participants who were enrolled in a behavioural weight-loss program in addition to receiving motivational interviews would experience a greater reduction in their body weight by the end of the program and at 6 months follow-up.It was hypothesized that when compared to a control group, these participants would adhere to behavioural weight-loss programs to a greater degree and report greater importance, confidence, and readiness to change their behaviour.
The researchers recruited 135 participants (105 women and 30 males) between September 2007 and May 2009 who had voluntarily self-enrolled in a 12 week, 24-session behavioural weight-loss program (TrymGym) at the University of Calgary. The participants were required to be at least 18 years old and have a Body Mass Index range of obesity or overweight (BMI ≥25 kg/m2). Participants were randomly assigned to the experimental (BWLP + MI) or control group(MI only) group and were excluded if they were concurrently involved in another weight loss treatment program.
Motivational Interviews Did Not Enhance Weight Loss
The study results showed that even though participants in both groups experienced a reduction in weight from baseline to the end of the weight loss program, the addition of motivational interviews did not further enhance the weight loss. Furthermore, participants who were exposed to motivational interviews were no more likely than the control group to attend more treatment sessions or to report that the motivational interviews had a greater effect on the importance of, readiness for, and confidence for change.
A limitation of the study was that there may not have been enough motivational interviews to improve weight-loss outcomes. This study included only two sessions of motivational interviews and that may have influenced the conclusions that were drawn regarding the benefit of motivational interviews on behavioural weight-loss programs. Another limitation was due to the fact that researchers relied on self-reported data from participants, which could have possibly introduced a self-reporting bias when interpreting the results. It is possible that the participants who volunteered for this weight loss study were already highly motivated to lose weight, and that is why the motivational interviews had no impact – they were simply not needed. Lastly, the participant population was comprised mainly of white individuals with a high socioeconomic status which makes it difficult to generalize the findings to other populations.
In conclusion, there was no indication that combining motivational interviews to behavioural weight-loss programs resulted in increased weight loss, or improved motivational constructs. At this time it cannot be considered an important component of a successful weight loss treatment program.
Written By: Kimberly Spencer B.Sc. (Hons)
Moss, Erin L. et al. “Behavioral Weight-Loss Treatment Plus Motivational Interviewing Versus Attention Control: Lessons Learned From A Randomized Controlled Trial.” Trials, vol 18, no. 1, 2017, Springer Nature, doi:10.1186/s13063-017-2094-1.