Effect of Mindful Eating on Weight Management in Breast Cancer Survivors

Expérimental: Mindful eating intervention

The mindful eating intervention was taught by a mindfulness-based stress reduction instructor certified by the Center of Mindfulness at the University of Massachusetts Medical School.

Comportemental: Mindful eating intervention

A Mindful Eating Workshop™ workbook was used for standardization and reproducibility of these sessions. The group sessions were focused on teaching applied strategies to consume food with intention and attention and aimed at improving emotional relationships with food. Intervention sessions were held once a week in the evening for 2 hours per session over 8 weeks. The intervention was delivered in a large conference room on the University of Georgia campus. Participants were required to attend seven out of eight sessions. If participants missed a session, they met with the instructor 30 minutes before the beginning of the following week's session to receive individual instruction on content of the missed session.

Body Mass Index

At the baseline and follow-up visits, trained study staff measured participants' weight and height using a standardized protocol. Height (measured by a stadiometer to the nearest 0.1 cm) and weight (measured by a scale to the nearest 0.1 kg) was used to calculate BMI (weight in kg divided by height in m²).

Blood Pressure

At the baseline and follow-up visits, trained study staff measured participants' systolic/diastolic blood pressure using a standardized protocol to the nearest mmHg. In order to ensure reliability, all measurements were taken 3 times and average values were used for analyses.

Waste and Hip Circumference

At the baseline and follow-up visits, trained study staff measured participants' waist and hip circumference by tape measure to the nearest 0.1 centimeter.

Body Fat Percentage

At the baseline and follow-up visits, trained study staff measured participants' body fat percentage using a bioelectrical impedance analyzer (BIA).

Feasibility of Conducting the Intervention

Feasibility was assessed by tracking participant accrual and retention rates.

Acceptability of the Intervention

To measure acceptability, participants were asked to complete a 5-question feedback survey to evaluate the mindful eating intervention at the follow-up study visit. Specifically, the open-ended survey questions asked participants about (1) their experience with intervention, (2) how the intervention affected diet and exercise management, (3) positive aspects about the intervention, (4) negative aspects about the intervention, and (5) suggested changes to the intervention. Qualitative data analysis techniques were used to identify themes within the data.

Mindful Eating Measures

Changes in mindfulness resulting from the intervention were measured using the validated Mindful Attention Awareness Scale (MAAS). The MAAS questionnaire is a 15-item scale that was designed to assess mindfulness and receptive awareness throughout an individual's daily life. Scores from the MAAS range from 1 to 6, with higher scores associated with higher mindfulness. The MAAS was validated for use in cancer populations against the Profile of Mood States (POMS) scale that is widely used in clinical settings. Higher MAAS scores were significantly correlated with lower POMS scores, further confirming the construct validity of the MAAS questionnaire for assessing mindfulness in cancer populations. The questionnaire was self-administered to the participants pre and post intervention.

Nutritional Intake

Habitual nutritional intake was measured using an electronic version of the Block Food Frequency Questionnaire, a 127-item food and beverage recall instrument referencing the consumption over the past month. Dietary intake data was describes as daily energy consumption (kcal), consumption of macronutrients (fat, protein, carbohydrate; grams/day), and intake of sweets (% of daily intake) to compare intake before intervention start with intake during the intervention.

Physical Activity

Participants' physical activity levels (average daily steps; moderate-to-vigorous physical activity (MVPA) minutes) were tracked throughout the study period using FitBit® Flex accelerometers. Total daily steps and MVPA minutes were averaged for the first and the last week of the intervention to examine changes.