A study released by the Humane Research Council (HRC) - a nonprofit that provides public opinion research for use by animal advocacy groups - says at least 86% of vegetarians go back to eating meat at some point in their lives.
Vegans, however, are more likely to stick to their beliefs, with only 70% sliding back into the omnivore lifestyle.
The study goes on to say that the motivations to adopt a vegetarian or vegan diet are varied, with health, animal welfare, disgust by animal products, care for the environment, and taste all ranking highly.
But the major motivation that influenced now-former vegetarians and vegans was health, which suggests that those who adopt meatless diets primarily for their health benefits are less likely to stick to it.
The study used a large sampling of 11,399 respondents across multiple population groups in the US. The adults were chosen by Harris Interactive, the same company that does the well-respected Harris Poll.
Other startling figures from the study included that only 2% of the US population is currently vegetarian or vegan, but that 10% of the population have at one time or another identified as such.
According to Psychology Today, the implications of the study say that instead of calling for strict removal of meat and animal byproducts in our diets, we should instead look to reduce our intake of those foods.
The report argues that it would be much more productive to persuade people to reduce their animal consumption than to persuade everyone to give up animal products completely.
And for those quick to send this article gloatingly to high-minded vegetarian friends, be warned - 37% of the former vegetarians and vegans surveyed said they would consider adopting the diet again.
See the rest of the results from the study at HRC's website.