Intermittent fasting is one of the most popular dieting methods — and it’s no wonder why. Unlike keto or clean-eating, the emphasis of intermittent fasting is on when, not what, you eat. Many people therefore feel like they’re getting the best of both worlds: They can enjoy the foods they like and still reduce their intake of calories.
Research backs up this dieting technique, as well. A 2014 study published in the Cell Metabolism Journal, for instance, found that intermittent fasting helped reduce cases of obesity, hypertension, asthma, and rheumatoid arthritis. But is intermittent fasting successful at reducing all types of body fat? According to a study published this month in Cell Reports, belly fat may be tougher to tackle with fasting.
The study, which took place at the University of Sydney, examined the effects of intermittent fasting on adult mice for two weeks. Their data showed only very small changes in body weight. However, if the study had been extended to four weeks or more, the researchers believe that the fasting diet would likely have led to more weight loss.
But why did fasting do little to change the weight of the mice? Upon analyzing fat tissues in each mouse, scientists learned that visceral fat, which is stored in the abdomen, went into “preservation” mode. Even worse, visceral fat and subcutaneous fat (which is also stored in the belly) improved their ability to store energy as fat. This made it easier for the body to rebuild its fat store before the next fasting period.
Normally, fasting should cause the body to easily break down fat tissue (a process called lipolysis) into fatty acids, which then get used as energy. Visceral fat, however, became resistant to lipolysis. As a result, the mice did not lose as much of this unhealthy fat while fasting.
As explained in Harvard Health, there are two types of fat in the belly area: subcutaneous and visceral. Subcutaneous fat lies just underneath the skin, in front of the outer abdominal wall. Visceral fat, which is considered to be more harmful than subcutaneous fat, is stored in between the abdominal organs and in the omentum, a large flap of tissue covering the abdominal organs.
Why should you worry about visceral fat? Unfortunately, it is not simply a storage deposit that sits passively under the skin. As proven by research in the 1990s, all fat cells secrete hormones and other molecules that can affect the entire body. Some of these hormones are beneficial while others are not.
Visceral fat produces cytokines, which are small proteins that help cells communicate. Though cytokines play a vital role in the immune system, too many of them can cause inflammation and increase risk for heart disease and certain other illnesses.
According to the research team, the study showed that not all fat tissues are the same as many people think. In reality, the body stores several types of fat and the location of the fat is highly important.
This isn’t to say that fasting won’t help you lose weight. Many adults who try fasting regimens experience weight loss and visible fat loss. However, those adults may not be losing visceral fat, which is far less noticeable.
The visceral fat phenomenon may also explain why you stop losing weight after you’ve been on a diet for a while. With that in mind, you may want to switch up your dietary regime. It might help you break that plateau.