Intermittent fasting is a hot-button topic with people usually staunchly falling into two categories (those who think it’s the best thing since not eating sliced bread, and those who think it’s unnecessary). If you know someone who has lost weight with the intermittent fasting method, they probably appear to have lost it all over their bodies, right? A new study elaborates that intermittent fasting may only contribute to fat loss in certain areas of the body.
A research team at the University of Sydney used sophisticated instruments to study protein gene expression in fasting mice and found that following the every-other-day method did not work equally on different fat deposits within the body. This is a type of intermittent fasting which completely restricts eating any food on alternating days. Other types of intermittent fasting include the 5:2 rule where food is restricted 2 days a week, or the 16:8 rule where food is restricted daily for 16 hours and intake adheres to a strict 8-hour time-period.
The researchers found that among the other documented cascade effects that occur with intermittent fasting, it was belly fat which was resistant to this method. In fact, it actually resulted in the activation of a pathway which told the body to preserve the fat store, even in complete absence of caloric intake on the fasting days!
Belly fat can be some of the hardest fat to lose because it’s a type of fat that cushions the organs in the abdomen. This is visceral fat, and it’s different than fat that just exists under the skin in other parts of the bodies. Even though fat tissue is burned to give the body fuel when there is no caloric intake, visceral fat blocked the release of fatty acids from its tissues and inhibited fat burning.
Along with resisted fat burning (or lipolysis resistance), mitochondrial protein increased in fat tissue after every-other-day fasting, explaining an increase in fatty acid synthesis. Simply put, this is a sign that after experiencing every-other-day fasting, the body increased its ability to store fat as yet another preservation mechanism—not what you want to hear if you’re looking to burn fat with this method.
Don’t lose hope on intermittent fasting altogether, though. Intermittent fasting appears to trigger such a complex cascade of effects that liver health and muscle health have all been noted to benefit from it. IF is best done under the supervision of your doctor or nutritionist.
Further studies should be done to see if this belly fat resistance occurs with all methods of this dietary plan (such as the 5:2 or 16:8 methods, among others). If every-other-day fasting is working for you, keep up the good work!
Dylan J. Harney, Michelle Cielesh, Renee Chu, et al. Proteomics analysis of adipose depots after intermittent fasting reveals visceral fat preservation mechanisms. Cell Reports, 2021; 34 (9): 108804 DOI: 10.1016/j.celrep.2021.108804