Trying to lose belly fat by intermittent fasting? We might have some bad news for you. What type of intermittent fasting have you adopted?
In a mouse study, Australian researchers from the Univerity of Sydney discovered that belly fat goes into ‘preservation mode’ during some intermittent fasting regimens, adapting over time and becoming more resistant to weight loss.
Specifically, the research team led by Dr. Mark Larance examined fat tissue types from different locations to understand their role during every-other-day fasting, where no food was consumed on alternate days. As such, they have taken into account both the visceral “belly” fat, the fat tissue surrounding our organs, including the stomach, and the subcutaneous fat, which lies just under the skin.
“Our data show both visceral and subcutaneous fat undergo dramatic changes during intermittent fasting,” said Dr Larance, who is also a Cancer Institute of NSW Future Research Fellow.
Theoretically, during fasting, fat tissue is supposed to provide energy to the rest of the body by releasing fatty acid molecules. In reality, the researchers observed how visceral fat became resistant to this release of fatty acids during fasting. It also appeared that that visceral and subcutaneous fat increased their ability to store energy, likely to rapidly rebuild the fat store before the next fasting period.
“This type of adaptation may be the reason why visceral fat can be resistant to weight loss after long periods of dieting.”, concluded Dr. Larance.
Of course, you might say that this study was performed on mice. But the same behavior was already observed on human subjects. And besides, all these mouse studies have their benefits, too. As the researchers explain, “mouse physiology is similar to humans, but their metabolism is much faster, allowing us to observe changes more rapidly than in human trials, and examine tissues difficult to sample in humans.”
But this is not a piece of entirely bad news. The research team examined more than 8,500 proteins located in fat deposits, creating a map of changes that occurred during intermittent fasting. This lays the foundation for future studies, which will further investigate the individual molecules responsible for why visceral fat is resistant to energy release during fasting, and help determine what diet plans would be most beneficial for metabolic health.
Dr. Larance also says that their findings may not apply to different diet regimens, such as the 5:2 diet or calorie restriction, which are also common in people wanting to lose weight.
Source: Cell Reports