Towards a more custom tailored treatment of obesity: Subtyping the motivation to overeat.

Rationale:

Many obese individuals have tried to lose weight, however, few succeed in long-term maintenance of weight loss and weight is often regained after initial loss. It is clear that inducing a negative energy balance to produce weight loss is the key, but it is difficult to predict which obesity treatment or combination of treatment strategies are most likely to be successful in obese individuals or subgroups.



Objective:

We hypothesize that motivational and behavioral characteristics of eating behavior, in addition to genetic and environmental factors play a major role in the development of obesity. We aim to identify obesity subtypes based on these factors.
Study design: Observational with invasive measurements.



Study population:

Obese subjects from the obesity clinic at MC Zuiderzee, 18 - 70 yr old, both male and female.



Main study parameters/endpoints:

The classification of the obese into three subtypes for their motivation to overeat, and the role of genetic and biochemical variations. We expect to identify: 1) reward-prone/hedonic eaters, 2) Reward-deficient eaters, 3) Stress-activated eaters. After initial data analysis using conventional statistics, antropometric, psychological, biochemical and genetic data will be entered in a unique heterogeneous multi-agent system, developed and available at ATIA, allowing the identification of unexpected nonlinear correlations between parameters, providing information on previously unknown interactions, which will provide further insight in the development of obesity in our study participants.



Nature and extent of the burden and risks associated with participation, benefit and group relatedness:

The proposed studies are largely observational, therefore the risks associated with participation are low. Blood will be drawn on one occasion. Neuropsychological testing will also be done on one single occasion, and will take approx.. 2h. In consultation with the participants, we aim to combine the blood drawing and neuropsychological testing in one visit to MC Zuiderzee. Anthropometric data are collected routinely as part of the medical treatment protocol in these participants, so collection of these data do not form any additional burden for our study participants. Saliva sampling and D2O measurements can be performed at home, and saliva and urine samples collected at home will be returned to the investigators by mail. Participants will be notified of the study results, which will provide them with more insight in their motivation to overeat, and which will contribute to the development of subtype specific treatment protocols for obesity.

We hypothesize that motivational and behavioral characteristics of eating behavior, in addition to genetic and environmental factors play a major role in the development of obesity. We aim to identify obesity subtypes based on these factors.

This study will be cross-sectional.



Blood will be drawn for biochemical and genetic evaluation and neuropsychological evaluation will be performed using validated questionnaires and computer tasks. This will take approximately 2h. Participants will be asked to perform two take home tasks, a body composition assessment using double labeled water and a saliva cortisol awakening response test, which they will return by mail. Data on the medical history and physical examination will be obtained from the medical record, so that this will form no additional burden for the participants.

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