During a fasting state, fat tissue is broken down by a process called lipolysis, which releases fatty acids to provide energy to the body.
But, Larance says, not all fat is the same. Visceral fat, at higher levels, is associated with metabolic illness (such as cardiovascular disease and diabetes) and is a bigger problem in men. Subcutaneous fat – which lies just under the skin all over the body – provides some insulation and at moderate levels is linked to metabolic health. (There is also brown fat, which lies around the neck and shoulder blades, providing heat, but this study didn’t find changes to this tissue.)
Larance says the research uncovered a “striking change” in abdominal fat over two weeks whereby it downgraded its ability to break down via lipolysis. He says it’s possible that repeated bouts of fasting triggered a signalling pathway to protect its energy store.
“[It means] subcutaneous tissue is having to contribute more fatty acids.”
Of course, some people do experience weight loss while on an intermittent fasting diet. Larance says it’s unclear what fat is lost, but we usually carry more subcutaneous fat so losing it is more noticeable. He also says his study was on healthy mice who weren’t calorie reduced, so future research will examine whether effects differ on overweight subjects.
This content was originally published here.