Obesity: ‘Switch’ in brain controls weight gain


A faulty brain ‘switch’ may be responsible for immoderate weight gain, a new study shows.

New research has identified the mechanism through which the brain controls if and how much fat is burned after a meal. Faulty signals, the study has found, can promote obesity.

According to 2014 data from the World Health Organisation (WHO), more than 600 million adults around the globe are obese, and 41 million children younger than 5 years old are overweight.

In the United States, 36.5 per cent of the adult population, as well as around 17 per cent of children and adolescents, have obesity. A study recently covered by Medical News Today referred to exacerbated weight gain as a “pandemic” affecting the US and wider world.

This situation is particularly concerning because, according to the Centres for Disease Control and Prevention (CDC), excess weight can impact other health aspects, leading to high blood pressure, diabetes, coronary heart disease, and depression.

In light of this, a team of researchers from the Biomedicine Discovery Institute at Monash University in Melbourne, Australia, has recently conducted a study striving to gain a better understanding of the brain mechanisms that contribute to weight gain and loss.


The study found that the brain normally “instructs” the white fat cells to turn into brown ones after eating. This comes in response to insulin released into the bloodstream in larger quantities as blood glucose, or blood sugar, levels increase.

On the other hand, brown fat cells are turned back into white energy-storing fat cells after a period of abstinence, during which no food is consumed. When this mechanism functions normally, it allows the body to stabilize its weight, preventing excessive gain – or loss – of fat.

This mechanism, say the researchers, is akin to a switch, “reading” the insulin signals and flipping on and off as appropriate. In the case of people predisposed to excess weight gain, this switch malfunctions, becoming stuck in the “on” position.

“As a consequence, browning is turned off all the time and energy expenditure is decreased all the time, so when you eat, you don’t see a commensurate increase in energy expenditure – and that promotes weight gain.”

A previous study by Professor Tiganis and Dr Dodd examining the process by which white fat turns into brown spurred a lot of discussion on the topic, and it opened the door to other related research.

The scientists’ new findings further elucidate the implications of the brain’s response mechanism in the context of obesity.

“For a long time, the missing piece to the puzzle was always why this [browning of white fat cells] occurs in the body. We’ve shown not only why this occurs but also the fundamental mechanism involved. It’s very exciting,” says Dr Dodd.