As we all know, the habit of fat people often lies in being lazy, but why they are lazy first and then fat, or fat first and then lazy, is really a mystery. Recently, the journal "Cell Metabolism" revealed a study, by the research team of the National Institutes of Health of the United States, revealed the mystery, it turns out that obese people are difficult to keep exercising, the crux of which is the lack of a type of dopamine type 2 receptor (D2R).
Dopamine, which is a neurotransmitter in the brain, gives people pleasure and excitement, so it is called "happy substance", and it is essential for the production of action. Mr. Kravidz looked at obesity with his scientific eye and deduced that the lack of exercise in obese people may be related to the dysfunction of the dopamine system. So, he led the team to take the rats as the experimental subjects and follow this clue to explore the hidden secrets.
The team randomly divided the mice into two groups: one group with a light diet and the other group on a high-fat diet for 18 weeks. Sure enough, the rats on the high-fat diet are getting bloated, their activity time is drastically reduced, and their movements are slow. However, more importantly, the decrease in activity was seen before the weight gain was significant, indicating that overweight was not the only culprit of the loss of exercise.
In further exploration, the researchers examined the six key factors of the dopamine signaling pathway in the brains of two groups of mice, and found that the brains of obese and lazy mice lacked the dopamine type 2 receptor - that is, D2R. The experiment went one step further, and when the D2R in the normal mouse brain was artificially reduced, it also showed a state of reluctance to exercise, as if the lamp of vitality had been extinguished for no reason. The researchers took a different approach, using a drug-activated alternative receptor to mimic the action of D2R on neurons, as if a new switch was inserted next to a failover switch to adjust the dimming of the lights. The results were remarkable, when this "** receptor" was artificially activated, the exercise distance and frequency of obese mice increased significantly, confirming that the neurons regulated by D2R are indeed related to whether they are willing to exercise regardless of body size.
At this point, Kravidz's team has revealed one of the physiological causes of "obesity and laziness", and the problem does not stop there. They also asked: Does obesity lead to impaired D2R function? Conversely, if D2R is damaged, is it easy to fatten the rats?
In the re-experiment, the team removed D2R from some of the striatal neurons of mice, and even if they were not obese, the mice were lazy. However, despite the low willingness to exercise, the energy uptake and energy consumption of the control group were not significantly different from those of the control group after being fed a high-fat diet, and the rate of weight gain was also indistinguishable.
To sum up, Kravidz's research solves the mystery for us: fat people are not fat because they are lazy, but they are lazier because they are fat; However, laziness does not necessarily lead to obesity. As for the laziness of fat people, it is due to the dysfunction of the dopamine system caused by the lack of D2R receptors. The results of this study are like a ray of light, illuminating the tortuous road for us to understand the relationship between obesity and exercise, and also providing a new direction for thinking about improving the exercise habits of obese people in the future.