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There is an increasing trend in the incidence of obesity and associated health issues in society. Researchers have found that the brain chemical dopamine and the biological clock both play a role in this.
Obese People
A study led by Ali Guler, a professor of biology at the University of Virginia, shows a link between dopamine and the body clock, which influences food intake. It also reveals that the consumption of foods with a high-calorie content promotes overeating and obesity.
The new research appeared in the journal Current Biology.
There has been a considerable rise in obesity cases over the past few decades. In 1976, around 15 percent of adults in America were obese, according to researchers. But that figure has now risen to roughly 40 percent, with an extra 33 percent being overweight.
“The diet in the U.S. and other nations has changed dramatically in the last 50 years or so, with highly processed foods readily and cheaply available at any time of the day or night,” Guler said.
High amounts of sugars, carbohydrates, and calories in a good number of these foods lead to unhealthy outcomes.
Incidence of health problems, including scary ones such as diabetes, heart disease, and cancer, has been on the increase. Experts believe that obesity has a possible role in these disorders.
Excess body fat also possibly contributes to mental health issues, such as Alzheimer’s disease.
Guler and his colleagues showed that careless snacking could make a person become obese sooner or later.
Promotion of unhealthy eating and obesity
The research team made use of mouse models for their analysis. It investigated the influence that high-fat diet availability around the clock could have on body fat and health.
Researchers fed a group of mice a diet that was similar to a wild variety in calorie and fat content. They gave another group diets with high amounts of sugars, fats, and calories.
Guler and his colleagues observed that the wild-diet mice ate normally. The animals also upheld a normal level of activity. As a result, their body weight remained at a healthy level.
However, mice in the high-calorie diet group snacked at all times and so became obese.
Other research has shown that excess calories from high-fat diets or frequent snacking increase the store of fat in the body of mice, Guler noted. Over time, stored body fat can lead to obesity and associated medical conditions.
The researchers also found that the disruption of dopamine signaling resulted in normal eating. This made mice not to turn to a high-fat, high-calorie diet, even when such is available, in search of pleasure.
Dopamine and the biological clock
Dopamine is a key neurotransmitter and hormone involved in reward, pleasure, and motivation, among other functions. As for the biological clock, it is the body’s internal clock that regulates sleeping and waking.
The current study shows that both dopamine and the biological clock are linked.
“We have shown that dopamine signaling in the brain governs circadian biology and leads to consumption of energy-dense foods between meals and during odd hours,” said Guler.
According to the biology professor, the human body has evolved to demand more food as long as such is on hand. This is a form of adaptation for dealing with periods of scarcity. The body stores up fat from food consumption because of uncertainty over the timing of the next meal.
Unlike in the past, more foods are available today, so there is no need for excessive eating. This availability, however, now means more opportunities to overeat.
Sadly, human diets in modern times, especially in the West, feature a lot of unhealthy foods. Guler stated that high amounts of calories could now be crammed into small-sized food items, thereby increasing the risk of obesity.
In addition, people now work and play 24/7, aided by regular, stable electricity and advanced technologies. This has led to the disruption of the biological clocks of many people and to unhealthy eating habits.
In olden times, people worked in the daytime and went to bed when it got dark. This promoted a normal sleep-wake cycle.
“This lights-on-all-time, eat-at-any-time lifestyle recasts eating patterns and affects how the body utilizes energy,” Guler said. “It alters metabolism, as our study shows – and leads to obesity, which causes diseases.”
Obesity makes worse half of the medical disorders that affect humans, according to him.
The researchers said that how often a person eats is as important as the quantity of food they consume.
References
Grippo, R. M., Tang, Q., Zhang, Q., Chadwick, S. R., Gao, Y., Altherr, E. B., Sipe, L., Purohit, A. M., Purohit, N. M., Sunkara, M. D., Cios, K. J., Sidikpramana, M., Spano, A. J., Campbell, J. N., Steele, A. D., Hirsh, J., Deppmann, C. D., Wu, M., Scott, M. M., & Güler, A. D. (2020). Dopamine signaling in the suprachiasmatic nucleus enables weight gain associated with hedonic feeding. Current Biology, 30(2), 196–208.e8. https://doi.org/10.1016/j.cub.2019.11.029
Blancas-Velazquez, A., Mendoza, J., Garcia, A. N., & la Fleur, S. E. (2017). Diet-induced obesity and circadian disruption of feeding behavior. Frontiers in Neuroscience, 11, 23. https://doi.org/10.3389/fnins.2017.00023
