In a study with mice, Australian researchers mapped what happens behind the scenes in fat tissue during intermittent fasting, showing that it triggers a cascade of dramatic changes, depending on the type of fat deposits and where they are located around the body.
Using state-of-the-art instruments, researchers at the University of Sydney found that the fat around the stomach, which can accumulate in a ‘protuberant belly’ in humans, goes into ‘conservation mode’, adapting over time and becoming more resilient to weight loss. The findings are published today in Cell Reports.
Types of belly fat
A research team led by Dr. Mark Larance examined the types of fat tissue from different locations to understand their function during fasting every other day, where no food was consumed on alternate days. The types of fat where changes were found included visceral “belly” fat, which is the fatty tissue that wraps our organs, including the stomach; and subcutaneous fat, which is found just underneath the skin and is associated with a better metabolic health.
“While most people would think that all fat tissue is created the same, in fact, location makes a big difference,” lead author Dr. Larance pointed out. He is a member of the Charles Perkins Center and the School of Life and Environmental Sciences of the University of Sydney. “Our data shows that both visceral and subcutaneous fat suffer dramatic changes during intermittent fasting,” said Dr. Larance, who is also a NSW Cancer Institute Future Research Fellow.
Why Visceral Fat May Be Resistant To Weight Loss
During fasting, fat tissue provides energy to the rest of the body by releasing fatty acid molecules. Nevertheless, the researchers found that visceral fat became resistant to the release of these fatty acids during fasting. There were also signs that visceral and subcutaneous fat increased their ability to store energy in the form of fat, which would probably quickly rebuild the fat deposits before the next period of fasting.
Dr. Larance said it was possible that a history of repeated fasting periods triggered a preservation signaling pathway in visceral fat. “This suggests that visceral fat can adapt to repeated fasting episodes and protect your energy reserves,” he said. “This type of adaptation may be the reason why that visceral fat can be resistant to weight loss after long periods of dieting.”
Dr. Larance said that using a mouse model was a useful analog test before human studies. “The physiology of mice is similar to that of humans, but their metabolism is much faster, which allows us to observe changes more quickly than in human trials and to examine tissues that are difficult to sample in humans,” Dr. Larance said. Future research in mice and humans could discover the mechanisms through which this resistance occurs and also what types of diet and other interventions may be best to fight abdominal fat.
Mapping the inner workings of fat deposits
The research team examined more than 8,500 proteins located in fat deposits, creating a catalog of changes that occurred during intermittent fasting, using a technique called proteomics. Proteomics, the study of all proteins, a relatively new area of study that takes its name from genomics (the study of all genes), monitors how proteins react under certain conditions, in this case, intermittent fasting.
The results provide a rich source of data that helps to get a more complete picture of the inner workings of fat tissue. It was through proteomics that the research team was alerted of the main cellular changes caused by intermittent fasting and after further analysis, highlighted the visceral fat conservation mechanism in action. The study was performed using mass spectrometry instruments at the Charles Perkins Center, which is part of the main research facilities of the University of Sydney.
Future research needed
Dr. Larance said that it should be noted that the findings from the intermittent fasting study may not apply to different diet regimes, such as the 5:2 diet (2 days of fasting out of 7) or calorie restriction, which is popular among people who want to lose weight. The results lay the foundations for future studies, which will analyze the molecules responsible for why visceral fat is resistant to energy release during fasting and will help determine which diet plans would be most beneficial for metabolic health.
“This type of research which has been possible thanks to these new instruments that allow us to ‘look beyond the street light’ – is generating hypotheses; we knew we would find something, but we didn’t know what,” Dr. Larance explained. “Now that we have shown that ‘belly fat’ in mice is resistant to this type of diet, the big question will be to answer why and how we can best address this.”
Reference: Harney dj, Cielesh M, Chu R, et al. Proteomics analysis of adipose depots after intermittent fasting reveals visceral fat preservation mechanisms. Cell Reports 34, 108804 March 2, 2021.
Link: https://www.sochob.cl/web1/grasa-abdominal-resistente-al-ayuno-cada-dos-dias/
Date: March 3rd, 2021
Source: https://medicalxpress.com
