Ever feel like you’re eating healthy and exercising, but still gain weight — or at least don’t lose it? It turns out, you’re not imagining things. A new study shows that it’s scientifically harder for adults today to maintain a healthy weight than it was for our parents — even with the same amount of food intake and exercise.

A recent study published in Obesity Research & Clinical Practice found out that adults today have it rough when it comes to weight loss, and even just weight management. Despite the same amount of food intake and exercise, it’s harder for adults today to maintain their weight than it was for adults 20-30 years ago. In fact, a person today is likely to weigh 10% more than a person in the 1980s with the same diet and exercise.

The authors came to this surprising conclusion by analyzing the food intake of over 36,000 Americans between 1971-2008, and the physical activity of nearly 15,000 people between 1988-2006. By grouping the data together by the amount of food and activity, age, and BMI, they found out that weight loss and management was just plain easier back in our parents’ day.

“Our study suggests that if you are 25, you’d have to eat even less and exercise more than those older, to prevent gaining weight,” said Jennifer Kuk, a professor of health science at York University involved in the study in a statement. “However, it also indicates there may be other specific changes contributing to the rise in obesity beyond just diet and exercise.”

It’s not because our diets today are less nutritious or because we spend more time playing video games instead of exploring the great outdoors. The study compared a person in 2006 who ate the same amount of calories, including the same amount of important nutrients like protein and fat, as a person the same age in 1988. And even exercising just as much, today’s adult would have a BMI that’s about 2.3 points higher.

What are those changes? All we know right now is hypothesis.

The rise in average weight may be correlated with the increased use of weight-gain inducing chemicals around us. From pesticides to substances in food packaging, it’s hard to predict what effect these chemicals have on our hormones and weight management. And, unfortunately, they’re nearly impossible to avoid.

Another element to blame is in our own bodies: the study authors believe that the bacteria in our gut has somehow changed since 30 years ago. It’s already known that certain types of gut bacteria make people more prone to gain weight. It’s possible that the combination of Americans eating more meat (especially from animals treated with more hormones and antibiotics) and more artificial sweeteners has played a role in our weight gain.

Though a few decades ago this kind of study would strike fear into people’s hearts, the good news is that we’re in the midst of a powerful and important body positive movement—a collective push away from traditional beauty standards and towards an understanding that all body types are beautiful. As Kuk points out, this study could pave the way for more body acceptance, as people may accept finally that there are factors outside an individual’s control when it comes to weight.

“There’s a huge weight bias against people with obesity,” Kuk said. “They’re judged as lazy and self-indulgent. That’s really not the case.”

Preach. Especially given this new data, it’s time to embrace overall health and body acceptance, and make uneducated judgments a thing of the past.

(Image via iStock)