The paper talks about epigenetics and these chemicals, but isn't it possible the diet and lack of physical activity affected future generations as well? If not

The paper talks about epigenetics and these chemicals, but isn't it possible the diet and lack of physical activity affected future generations as well? If not via epigenetics, perhaps via gut flora being passed down and spread? They talk about lab animals with controlled diets and activity becoming fatter on average over the decades, and point to chemicals as the only possible culprit. I find that quite possible or even probable, but isn't it also possible the gut flora is evolving to be more efficient at processing modern food?