French fries. Freedom fries. Pomme frites. Chips.

No matter what you call them, there’s no denying the deliciousness of these sometimes-deep fried, sometimes-baked culinary staples. It’s hard to imagine a summertime burger without a basket of fries to go along with it. But if you’re watching your waistline (or your cholesterol, or your salt intake), you might actually have to deny them. And to make things worse, you might have to deny them while dining with that one skinny friend who can eat an entire plateful of fries without one single dire consequence.

According to new research from the Harvard School of Public Health, however, it might not be wise to blame your friend. Blame biology instead.

The data, reported earlier this week in the British Medical Journal, shows that people who are more genetically inclined to be obese tend to pack on more pounds when they eat fried foods than those who aren’t. And as NPR’s Michaeleen Doucleff points out, “The effect isn’t huge. But for some people, the extra pounds could be the difference between being ‘normal’ weight and overweight.”

Basically, the difference can be broken down like this. If you’re carrying 10 obesity risk genes and you scarf down French fries at least four times in a given week, you’re bound to give yourself two extra points on the BMI scale, a measurement for your body fat. If you don’t have those particular genes, one of those points simply won’t affect you at all. That means that yes, certain folks do suffer more physical health problems from eating excess amounts of fried foods — and now we have the science to prove it.

Those results were found after studying the eating habits of 10,000 women and 6,500 men from the Nurses’ Health Study and an additional 20,000 women from the Women’s Genome Health Study. It was one of the largest studies ever conducted to tackle this particular connection, Healthline reports.

Research like this is increasingly necessary in the United States today as obesity continues to be a plague upon the American people. Currently, it’s projected that more than a third of all U.S. adults are obese, and those numbers keep rising. As the problem inches closer to more costly proportions — $147 billion per year, in fact — the dieting and healthy lifestyle industry is seeing a bit of a boom itself.

“I think when a person is being raised in a family, there are obviously habits that are developed,” explains Beth Golden, PhD, ND, educator and formulator of the Raspberry Ketone Diet Plan. “Parents in certain families use food for comfort, and their children do too. It’s a learned behavior. Because foods are chemicals, they can create more ceratonin, which can help children feel better, while also forming an emotional bond.”

“From a genetic standpoint, we know that the hypothalmus gland regulates and controls many functions and systems in the body, including metabolism,” continues Golden. “It’s been proven that if that glad is out of balance through stress or trauma, that people can gain weight. A person can also have organs or systems that can make them more inclined to gain weight. Certain predisposed conditions can stem from previous generations.”

The next time you’re flirting with ordering a plate of piping poutine or sizzling seasoned curly fries, ask yourself if it’s worth the price of your waistline. Or you can take your chances and bet on your biology. The choices are yours and yours alone.