According to new research out of City of Hope and UCLA, the expansion of your belly that coincides with the increase in your age doesn’t have as much to do with overeating or eating too many processed foods as much as it has to do with your body being biologically programmed to grow that extra padding as you age.

Sure, a bad diet and lack of exercise are probably contributing. But, as with so many issues we have with our bodies, it all comes down to our biology.

In a study published in Science, researchers discovered that white adipose tissue, aka belly fat, ramps up production in middle age. This is thanks to a type of stem cell called CP-As, or “committed preadipocytes, age-specific.” CP-As pretty much exclusively churn out new fat cells, making them solely responsible for your middle-aged weight gain despite your best efforts.

Why Your Body Suddenly Starts Stashing Belly Fat in Middle Age

With the aid of mice and single-cell RNA sequencing, scientists transplanted stem cells from older mice into young mice. This made them crank out fat like they were just beginning their decline rather than being in the prime of their lives.

In older mice, these CP-A cells needed a specific signal, called the LIFR pathway, to light up and multiply. Yes, all of this was with laboratory mice, but the researchers found the same CP-A cells in human fat tissue.

This opens the door to potential future therapies that could block CP-As or the LIFR signal. That would possibly give us a way to stop the slow descent into the doughiness of middle age.

Until then, we can take solace in knowing that it’s not just our uncontrollable urge to demolish an entire bag of Cheetos while standing in the kitchen at 2 AM, it’s also some stupid cells we also can’t control.

Pair all of this with the fact that if you lose any of this weight, your body is programmed to remember being fat thus making it easier to regain the weight, and it becomes abundantly clear that many of the thin middle-aged people you know are probably getting a little bit of help beyond diet and exercise.