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• To examine whether the addition of motivational interviewing (MI) to a culturally-targeted group-based behavioral weight loss program for African American (AA) women enhanced adherence to the group program
• To explore the effect of MI on diet and physical activity behaviors and weight loss outcomes
• To examine whether MI increased internal motivation for weight loss and self-efficacy for diet and exercise.

The women were recruited from a community health center serving predominantly lower-income AAs. Eligibly criteria included: 

• 18 years or older
• Obese (BMI=30 to 50)
• Not pregnant or intending to become pregnant within six months
• Not currently involved in other weight loss treatments
• Free from psychiatric illness or substance abuse
• Able to walk continuously for at least 10 minutes
• Not planning to move out of the area (Kansas City, MO area) within six months
• Able to obtain medical clearance from a primary care provider.

The authors did not indicate how they defined African American, nor did they list it as an inclusion criteria; however, being African American was defined as an inclusion criteria throughout the study.

Subjects that did not meet the inclusion criteria were excluded.

Recruitment

African American women were recruited from a community health center serving predominantly lower-income African Americans and the surrounding community in Kansas City, Missouri. They were recruited using flyers, a staffed table in the health clinic lobby and by word of mouth.

Design

This was a randomized controlled trial. Participants were randomized to receive four individual session of MI or health-education (HE for attention control) as an adjunct to a 16-week culturally targeted behavioral weight loss program.

Blinding Used

After recruitment and screening, participants were randomized  sequentially using a closed-envelope procedure that was created by the study statistician. The investigators and data collection staff were concealed from this information. 

Intervention

• All subjects received the  16 session behavioral weight loss program, which was adapted from the "Lifestyle Balance" program of the Diabetes Prevention Program (DPP). The program was administered in 90-minute weekly sessions in groups of 12 to 14 participants.
• MI and HE participants were in the same groups to ensure comparable groups across conditions
• A doctorate-level psychologist and a masters-level counselor or dietitian led each group, following a treatment manual. During the first 30 minutes, the participants weighed in, reviewed weekly self-monitoring logs, and shared strategies with the group. The  next 60 minutes addressed the weekly topic, which included nutrition and physical activity education and behavioral modification skill building.   
• Cultural adaptations were identified from previous work and included:
  • Social support
  • Addressing barriers related to transportation, neighborhood safety, literacy and other stressors
  • Guidance about food and physical activity (PA) were made relevant to cultural practices 
  • Preferences for larger body sizes were recognized
  • AA community leaders who had succeeded at weight loss were invited as peer mentors
  • Participants developed group names for themselves (e.g., Jazzy Women Taking It Off and Dedicated Divas) to increase ownership
  • Sessions were less didactic and more interactive in nature
• The subjects randomized to MI received four separate 30-minute individual MI sessions with an advanced doctoral clinical psychology student. The same counselor provided all four sessions. This counselor did not facilitate the group sessions with their given participants.  
• The MI sessions occurred at weeks zero (in-person), three (by phone), eight (in-person) and 13 (by phone). Consistent with MI, the majority of each session was spent eliciting change talk by exploring motivation

Statistical Analysis

• Baseline differences between MI and HE conditions and participants retained and those lost to follow-up were tested using two-sample T-tests and chi-square analyses
• Two-sample T-tests were used to compare MI and HE conditions on satisfaction and adherence variables
• Main effects of treatment on pre- to post-treatment outcomes were analyzed using two-way repeated measures ANOVA with treatment condition as the between-group factor. Participants were analyzed in the condition to which they were randomized.

 

Timing of Measurements

• Program adherence was measured weekly
• Satisfactions with the entire program plus intervention was measured post-treatment (week 16)
• Dietary intake, physical activity, weight, height, motivation, self-efficacy for diet and exercise were measured at baseline and at 16 weeks.

Dependent Variables

• Weight: Measured without shoes using a digital scale to the nearest 0.1. Weight was then adjusted (decreased) by two pounds to account for clothing.
• Height: Without shoes, rounding to the nearest 0.25 inch
• BMI: The height and weight were used to calculate the BMI
• The outcome variables of energy intake, percent calories from fat  and fruit and vegetable consumption  were obtained using 24-hour dietary recalls. These were conducted using the USDA multiple pass approach using three days of recalls . 
• Adherence to the behavioral weight loss program: Attendance, number of self-monitoring logs turned in and level of completion of self-monitoring logs
• internal motivation: Measured using the six-item autonomous regulation scale of the Treatment Self-Regulation Questionnaire
• Self-efficacy: This measure was adapted from a tool developed by Bandure to assess confidence in the ability to overcome common barriers to regulating healthy eating and exercise. Eight items were removed from the measurement tool that were felt to be less relevant and two were added for assessing exercise self-efficacy. 

 Independent Variables

• Four sessions of motivational interviewing sessions, delivered at week zero, week three, week eight and week 13
• Attention control group: Four health education sessions delivered on the same time frame as those randomized to receive the MI sessions. The participants chose four topics from six options (breast, colon or cervical cancer screening; smoking cessation; helping others quit smoking; and improving sleep). 

 Control Variables

 All subjects received the 16-session behavioral weight loss program that was adapted from the "Lifestyle Balance" program of the Diabetes Prevention Program (DPP). The program was administered in 90-minute weekly sessions in groups of 12 to 14 participants. MI and HE participants were in the same groups to ensure comparable groups across conditions. 

• Initial N: Total (N=44); MI (N=21); HE (N=23)
• Final N: Lost to follow-up in MI (N=6); lost to follow-up in HE (N=4)
• Age: All subjects 44.3±11.6; MI 41.6±12.3; HE 47.2±10.4
• Other relevant demographics: Education, marital status, employment status, co-morbid medical conditions, previous weight loss attempts, BMI, weight, baseline dietary intake, percent kcal from fat, total fruit and vegetable intake, baseline physical activity levels, internal motivation, dietary self-efficacy and PA self-efficacy were all analyzed and baseline data presented. No significant differences were found between the MI group and the HE group.  
• Location: Kansas City, Missouri.

 

 

Means, Standard Deviations and Effect Sizes for Change in Diet, Physical Activity, Weight and Psychosocial Factors by Total Sample and Treatment Condition
Variable	MI (N=14)	HE (N=19)	Total (N=33)	Cohen’s d BG
Diet
Total kcals per day	-434 (538)	-486 (801)	-465 (696)	- 0.08
Percent of kcals from fat	-3.4 (9.1)	-5.5 (7.7)	(8.2) -0.25	-0.25
Fruit and vegetable servings per day	1.2 (2.8)	2.0 (3.2)	1.7 (3.0)	-0.27
Physical activity
Kcal per week per kg	5.4 (31.1)	8.3 (20.4)	7.0 (25.1)	-0.11
Activity minutes	92 (435)	108 (282)	101 (350)	-0.04
Weight
Weight (kg)	-2.6 (4.2)	-3.2 (5.7)	-3.0 (5.1)	-0.12
BMI	-1.0 (1.5)	-1.1 (2.0)	-1.1 (1.8)	-0.06

Other Findings

• The addition of MI to this weight loss program did not improve adherence or treatment outcomes
• Main effects for condition were not statistically significant for diet, physical activity or weight outcomes. There was change over time for both groups, with a decrease in kcals, percent of kcals from fat and an increase in fruit and vegetable consumption for both the MI and HE group. 
• Those receiving MI were more satisfied, but not more likely to attend the group interventions, to change their dietary intake or physical activity or to lose weight compared to women who received a HE attention control
• Women in both conditions also both reported decreases in motivation and self-efficacy. Those who were higher in these variables at baseline had greater decreases over time, but treatment group did not matter. 

 

This study suggests that MI may not be as effective with AA populations as Caucasians for weight loss and health behavior change. Further work is needed to replicate this finding and dismantle the SES barriers versus sociocultural factors that may limit the impact of MI. 

Not-for-profit

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This is a well-designed study with a clearly defined study question and secondary questions as well. The findings suggest that we have a long way to go in determining how cultural components play into behavior change programs for long-term weight loss success.