A new study finds that the same calories and exercise today result in higher BMI than 30 years ago.
Obesity is such a mounting health issue in the western world, and it’s easy to point our fingers at the standard American diet and its depressing glut of processed foods. But a recent study published in the journal Obesity Research & Clinical Practice found that there may be more to the picture than meets the eye.
The authors analyzed the dietary data of over 50,000 Americans between the years 1971 and 2008 and found a very surprising correlation: "A given person, in 2006, eating the same amount of calories, taking in the same quantities of macronutrients like protein and fat, and exercising the same amount as a person of the same age did in 1988 would have a BMI that was about 2.3 points higher," according to The Atlantic.Which is to say, with the same diet plan and exercise routine, a person nowadays would be 10 percent heavier than their counterpart in the 80s.
“Our study results suggest that if you are 25, you’d have to eat even less and exercise more than those older, to prevent gaining weight,” says Jennifer Kuk, a professor from Toronto’s York University.
“However," she adds, "it also indicates there may be other specific changes contributing to the rise in obesity beyond just diet and exercise.”
So what’s behind this mysterious collective weight gain? There’s not one confirmed answer, but Kuk and the study's other authors have some ideas about what could be at play.
She notes that there are a number of environmental chemicals that are potentially weight inducing. Everything from pesticides and flame retardants to BPA and phthalates are suspected of altering our hormonal processes and confusing the way we gain and maintain weight.
Next up, prescription drugs, of whose use has skyrocketed in the last few decades. Prozac was introduced in 1988, now antidepressants are one of the most prescribed drugs in the US and many of them have weight gain as a side effect.
Finally comes the idea that our microbiomes have changed. We know that some types of gut bacteria contribute to weight gain and obesity. Americans are eating more meat now, as well as the hormones and antibiotics that are used in raising livestock – the study authors say this could be changing gut bacteria slowly at first, but with a cumulative effect. Kuk thinks that artificial sweeteners could be at play as well.
That Americans today may weigh more because of things beyond their control is good reason, Kuk says, for us to be more accepting of people with all body types.
“There's a huge weight bias against people with obesity,” she says. “They're judged as lazy and self-indulgent. That's really not the case. If our research is correct, you need to eat even less and exercise even more” just to be same weight as your parents were at your age.
Which may be simplifying things because ultimately we are all responsible for taking care of our own health ... but that modern life may be a contributing factor is an interesting twist to mix into the diet plan.