A study published recently in the journal Obesity Research & Clinical Practicefound that it’s harder for adults today to maintain the same weight as those 20 to 30 years ago did, even at the same levels of food intake and exercise.

What do you think of some of the theories about why this might be? The author lists:

[P]eople are exposed to more chemicals that might be weight-gain inducing.

Second, the use of prescription drugs has risen dramatically since the ‘70s and ‘80s. Prozac, the first blockbuster SSRI, came out in 1988.

Finally, Kuk and the other study authors think that the microbiomes of Americans might have somehow changed between the 1980s and now. It’s well known that some types of gut bacteria make a person more prone to weight gain and obesity.