Thesis Defense by Taylor Salinardi

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Title:

A WORKSITE-BASED DIETARY AND BEHAVIORAL INTERVENTION FOR WEIGHT LOSS AND OBESITY PREVENTION

Abstract:

Worksites offer great potential to become effective locations for reducing rates of overweight and obesity; however, the development and testing of innovative worksite weight control programs is needed to identify approaches that are most effective and sustainable. We conducted a 6-month, worksite-randomized controlled pilot study aimed to determine whether a dietary and behavioral intervention in worksites in the Greater Boston area would lead to significant changes in body weight and cardiometabolic risk factors for chronic disease. The intervention combined recommendations to consume a reduced energy, high fiber, low glycemic load diet with education on nutrition and behavior change, and a subsequent 6-month structured weight maintenance program. Concurrently, a low-intensity health and nutrition education program was available to all employees. Furthermore, a sub-group of employees underwent functional magnetic resonance imaging (fMRI) to examine changes in region-specific brain activation in response to high-calorie and low-calorie food images before and after participation in the weight loss intervention. Mean weight loss was substantial in program participants whereas wait-listed controls gained weight (-8.0 ± 0.7kg versus +0.9 ± 0.5kg, P<0.0001). There were improvements in cardiometabolic risk factors in intervention subjects as compared to controls: fasting total cholesterol (-13.21 ± 2.95mg/dl versus +0.76 ± 3.74mg/dl, P=0.01), LDL-C (-13.47 ± 2.67mg/dl versus -4.70 ± 3.94mg/dl, P=0.05), glucose (-6.37 ± 1.55mg/dl versus +6.31 ± 3.55mg/dl, P<0.001), systolic blood pressure (-8.51 ± 1.47mmHg versus +5.50 ± 2.08mmHg, P<0.0001), and in diastolic blood pressure (-8.14 ± 1.27mmHg versus -0.5 ± 1.28mmHg, P<0.001). There was no significant increase in body weight during the structured maintenance program (0.5  ± 0.7kg, P=0.65).Furthermore, overweight and obese employees in intervention worksites who did not enroll in the weight loss program also lost weight compared to those in the wait-listed control worksites (-1.3 ± 0.5kg versus +0.7 ± 0.6kg, P=0.03). In addition, there were changes in activation in regions of the prefrontal cortex, including the anterior cingulate and insula, as well as in the dorsal striatum in response to high-calorie and low-calorie food images among the sub-group of employees who underwent fMRI scans pre- and post-intervention. In conclusion, this pilot study demonstrated that worksites can be effective locations for achieving clinically significant reductions in body weight and improvements in cardiometabolic risk factors. Our findings also provide the first evidence that a dietary and behavioral intervention for weight loss can lead to differential changes in activation in response to high-calorie and low-calorie food stimuli in regions of the brain associated with food reward.

Friday, August 3, 2012
11:00 AM
HNRCA
711 Washington Street
Mezzanine Conference Room
Boston Campus

Committee Members:

• Susan Roberts, Chair
• Sai Krupa Das
• Alice Lichtenstein
• Thilo Deckersbach

All are welcome.

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