Title is misleading. This is across an entire population over generations. Should be changed to something similar to that. This sounds like it happens to an individual if they eat a vegetarian diet for a long period of time.
"Widespread vegetarian diets among a population could cause changes over time" is wholly different and apparently more accurate.
The title said "A" Vegetarian diet. It never referenced whom, what gender or the scope of the study, so in a literal sense, the title wasnt misleading at all.
I took the implication "A" Vegetarian diet, as in any or all contexts with in a long time period.