New Year Resolutions: Why It's Harder to Shed Pounds Each Year

As you get older, it's easier to pack on the pounds. As people make resolutions to lose weight this New Year, though, scientists have taken a closer look at why this is. Now, they've discovered why as we age, we tend to gain fat more easily and lose it more slowly.

In order to understand what mechanisms are at work when it comes to weight gain and weight loss, the researchers examined two groups of mice. The first group had the platelet-activating factor receptors (PAFR) gene knocked out. The second group was normal. In the end, the scientists found that PAFR-deficient mice developed a more severe obese state characterized by higher body and epididymal fat mass with age than that of wild-type littermates. Findings from the altered mice showed that PAFR-deficiency causes brown adipose tissue (BAT) dysfunction, which converges to induce the development of obesity, due to impaired thermogenic activity of BAT.

As we age, the thermogenic activity of brown fat is reduced. Brown fat is a "good" fat located in the backs of our necks that helps burn "bad" white fat around our bellies. In addition, the scientists also discovered a possible metabolic on/off switch that could reactivate brown fat.

"Future studies on how PAF/PAFR signaling controls UCP1 levels through beta3-AR production in the BAT of animals and humans may reveal new therapeutic targets to treat metabolic disorders associated with obesity," said Junko Sugatani, one of the researchers, in a news release.

The findings could lead to better treatments in the future. In addition, they reveal why older people need to work harder in order to shed the pounds. Our brown fat stops working as we age, which means that those who are older need to be prepared to eat more salads and lean proteins while logging more miles on the treadmill.

The findings are published in The FASEB Journal.