https://www.psychologytoday.com/blog/animals-and-us/201412/84-vegetarians-and-vegans-return-meat-why
The implications of this study are important. Only 2% of Americans do not eat any animal products. (This number has not changed appreciably for 20 years). Further, the fact that five out of six vegetarians go back to eating meat suggests that an all-veggie diet is very hard for most people to maintain over the long haul. Hence, the authors of the report argue that animal protectionists would be better off concentrating their efforts to persuade the many to reduce their consumption of flesh than trying to convince the few to take the absolutist route and give up meat completely. Sounds right to me.