According to Marketdata LLC, the U.S. weight-loss market was estimated to be worth an incredible $68.2 billion in 2017 alone. However, despite the amount of money spent on weight-loss, nearly 65% of all dieters return to their pre-dieting mass within three years, with only five percent of people who lose the pounds on a crash diet staying svelte. Therefore, a more medicalized intervention is needed in the sphere of weight-loss. Now, a study from researchers at McGill University shows higher-level brain functions have a major role in losing weight. The team states in their study involving 24 participants, those who achieved the greatest loss of mass demonstrated more activity in the brain regions of the lateral prefrontal cortex associated with self-control. The study is published in the journal Cell Metabolism.
Previous studies show evidence on the effectiveness of weight management programs often comes from uncontrolled program evaluations. Sparse data exists with regards to the neurocognitive pathways regulating the loss of weight and control, with insufficient responses to diets being attributed to hormonal adaptations overriding control of food intake. Two hormones, leptin, and ghrelin are known to trigger the body to eat in a diet-controlled setting, with levels of these hormones changing rapidly when adipose is shed. The current study uses fMRI neuroimaging to identify a neural signature and assess the roles these hormones have in achieving the loss of fat.
The current study follows 24 subjects in a dieting program using fMRI to assess the lateral prefrontal cortex, which is linked with self-regulation, and the ventral medial prefrontal cortex, a brain area involved in motivation, desire, and value. Subjects were shown pictures of appetizing foods as well as control pictures of scenery. Results show when participants are shown pictures of appetizing foods, the ventral medial prefrontal cortex area becomes more active on fMRI. Data findings show at one month and three months, the signal from the ventral prefrontal cortex declines in people who lost the most weight, with the lateral prefrontal cortex signal involved in self-control also increasing throughout the study.
Results show the brain region of self-control increased its activity and the region involving value decreased its activity, with the amount of change predictive of successful weight-loss. Data findings show the participants who achieved the greatest loss of adipose tissue had fMRI levels indicating a greater level of self-control, and, at the end of the 3-month study, the hormones ghrelin and leptin were starting to return to baseline, suggesting a new set point was achieved.
The team surmises they show activation in prefrontal regions associated with self-control contributes to successful weight-loss. For the future, the researchers state their data may lead to dieting treatments stimulating the prefrontal regions associated with self-control may contribute to successful loss of fat and maintenance.
Source: McGill University
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