Archive for September 20th, 2011
Sep 20 2011
Sep 20 2011
Tags: Diet, Health, Medicine, Obesity
Differences between euglycemic and hypoglycemic conditions.
Axial slices with (A) whole group, covaried for BMI (n = 14), (B) obese group (n = 5), and (C) nonobese group (n = 9) averages, showing brain response to euglycemia compared with mild hypoglycemia across visual cue tasks (threshold of P < 0.05, 2 tailed, FWE whole brain corrected). Red and yellow areas show greater activity during euglycemia, and blue areas indicate greater activity during hypoglycemia. The color scale gives the t value of the functional activity. Eu, euglycemia; Hypo, hypoglycemia; NAcc, nucleus accumbens; Hyp, hypothalamus; VMPFC, ventromedial prefrontal cortex; Hipp, hippocampus; L, left; R, right. MNI coordinates were used to define brain regions.
Yes, according to a new study.
If the brain goes hungry, Twinkies look a lot better, a study led by researchers at Yale University and the University of Southern California has found.
Obesity is a worldwide epidemic resulting in part from the ubiquity of high-calorie foods and food images. Whether obese and nonobese individuals regulate their desire to consume high-calorie foods differently is not clear. We set out to investigate the hypothesis that circulating levels of glucose, the primary fuel source for the brain, influence brain regions that regulate the motivation to consume high-calorie foods. Using functional MRI (fMRI) combined with a stepped hyperinsulinemic euglycemic-hypoglycemic clamp and behavioral measures of interest in food, we have shown here that mild hypoglycemia preferentially activates limbic-striatal brain regions in response to food cues to produce a greater desire for high-calorie foods. In contrast, euglycemia preferentially activated the medial prefrontal cortex and resulted in less interest in food stimuli. Indeed, higher circulating glucose levels predicted greater medial prefrontal cortex activation, and this response was absent in obese subjects. These findings demonstrate that circulating glucose modulates neural stimulatory and inhibitory control over food motivation and suggest that this glucose-linked restraining influence is lost in obesity. Strategies that temper postprandial reductions in glucose levels might reduce the risk of overeating, particularly in environments inundated with visual cues of high-calorie foods.
It is common knowledge in running endurance training (e.g. marathon training) that you need to maintain blood glucose levels in order to avoid “negative thoughts” from the brain. Thoughts that will persuade you to stop running.
So, why should this be any different throughout the day or evening when we are not stressing our bodies?
Interesting how obesity plays a role, where an obese person sort of loses their way with regulating their desires for high calorie food.