In recent years our understanding of the body's metabolic processes has progressed at an incredible pace. With rapidly increasing global rates of obesity, the race has been on to unlock the mysteries of how to manipulate the body's fat burning mechanisms. A team at Monash University recently made a major discovery, identifying the "switch" in the brain that controls how the body converts food into energy.
The majority of research around obesity has examined the way the body alternates production of its two major fat cells – white and brown. The production of these fat cells, called adipocytes, are directed by signals from the brain, with white fat cells produced to store energy, while brown fat cells are produced to expend energy.
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Research has shown these adipocytes are dynamic and can change from brown to white depending on direction from the brain. The team from Monash discovered in 2015 how the body executed this fat cell change, but the underlying mechanism that controlled the process was still a mystery.
The new study shows that after a meal, the brain senses the body's insulin levels and sends signals to generate either brown or white adipocytes. This on/off energy expenditure switch is coordinated by the hypothalamus through changes in the levels of a type of protein called T-Cell Protein Tyrosine Phosphatase (TCPTP).
The research found that, if the body is working properly, TCPTP is repressed when one consumes a meal. When TCPTP is inhibited the brain begins increasing its energy expenditure protocols, ultimately signaling production of brown fat. But this feeding-induced repression of hypothalamic TCPTP was found to be defective in the obese.
Across mouse studies it was found that mice lacking in hypothalamic TCPTP were resistant to diet-induced obesity, and when obese mice had hypothalamic TCPTP deleted from their system, they exhibited increased energy expenditure and feeding-induced brown fat conversion was restored.
This key mechanism may unlock the mystery of why some people struggle with obesity regardless of diet, while others seem to be able to eat anything and not gain significant weight.
"What happens in the context of obesity is that the switch stays on all the time – it doesn't turn on off during feeding," says lead researcher Professor Tony Tiganis. "Potentially we may be able to rewire this mechanism to promote energy expenditure and weight loss in obese individuals."
Of course, the researchers point out that this exciting prospect is still some time off. It is one thing to discover such as key mechanism as this, but actually finding a safe and effective way to manipulate it will take years of work.
However, this increased understanding into how the brain directs overall energy expenditure is still a major revelation for scientists and hopefully puts us on a path to overcoming the obesity epidemic.
The research was published in the journal Cell Metabolism.
Source: Monash University