Believe it or not, it used to be much easier to maintain a healthy weight back in the ’80s. That’s because a lot has happened in the past 40 years … and not for the better. Let’s take a look at an intriguing study that explores this disturbing trend.

Published in Obesity Research & Clinical Practice, the study found that people today have a higher average body-mass index (BMI) than people only a few decades ago. But here’s the kicker: The higher BMI is not the result of consuming more calories. In fact, the study found that a person today eating the same amounts of micronutrients (protein, fat, carb) and even exercising the same amount as a similar-age person in the 1980s would have a higher BMI.

OK, so if we can’t account for the difference based on age, exercise or calorie consumption habits, what does account for the difference? According to one of the researchers, possible explanations that deserve further investigation include some of the hazards of our modern, all-too-often “unnatural” world: exposure to chemicals that promote weight gain, prescription drugs, some of which also may lead to weight gain, and dietary habits (for example, artificial sweetener use, higher meat consumption) that may alter the gut microbiome. Talk to your doctor to learn more about how all three of these trends can negatively impact not just your weight, but also your overall health and wellness.