Veganism has a reputation for being sin-free, the martyr of all diets for saving animals, the human body and Earth itself.

While there’s plenty of evidence that avoiding animal products can benefit both a person’s health and the environment, it’s not necessarily the right eating plan for everyone. Plus, if all Americans were interested in going vegan — many signs point to this not being the case — it’s possible the country wouldn’t be able to sustain such a lifestyle. While the public often attributes going vegan as a way to lose weight, get healthy and treat the Earth better, there’s reason to believe this isn’t always the case. Absolutisms are rarely absolute.

Not all vegan diets are created equal

It’s possible to sustain a vegan diet on french fries and bagels alone — a nutritional profile that is nowhere near as good for you as, say, a piece of avocado toast topped with an egg.

French fries are often vegan, but not necessarily healthy.
French fries are often vegan, but not necessarily healthy. Studio_G/Shutterstock

No particular diet — not even the most nutritious vegan diet — is universally best, according to a large study published in the journal Cell. That’s because people can metabolize the same exact foods in different ways. “Our many years of research into nutrition and the microbiome showed that our response to any food (vegan or not) highly varies across individuals, leading to the conclusion that there is really no size-fits-all diet, and that includes vegan diets,” Eran Segal, one of the study’s researchers and co-author of The Personalized Diet, said in an email.

Vegan versions of non-vegan foods aren’t dependably more healthful. “Fake meat is often loaded with artificial ingredients, preservatives, processed oils and nutritionally empty ingredients,” vegan dietitian Megan Roosevelt told Livestrong. One report from the U.K.’s Consensus Action on Salt and Health found that veggie sausages can contain levels of salt similar to their meat-filled counterparts. Excess salt consumption has been linked to high blood pressure, a leading cause of cardiovascular disease. In summary: Just because it’s vegan doesn’t mean it’s good for you.

A vegan diet may not be the most sustainable diet

If U.S. farmers stopped producing animals for food and every American went vegan cold turkey, there wouldn’t be enough food to feed the country, according to a November report published in the journal Proceedings of the National Academy of Sciences.

Research suggests veganism might not be the most sustainable diet.
Research suggests veganism might not be the most sustainable diet. Anton Malina/Shutterstock

“Different types of carefully balanced diets — vegan, vegetarian, omnivore — can meet a person’s needs and keep them healthy, but this study examined balancing the needs of the entire nation with the foods we could produce from plants alone,” Mary Beth Hall, one of the study’s researchers and an Agricultural Research Service animal scientist at the U.S. Dairy Forage Research Center, said in a press release. “There’s a difference between what’s possible when feeding one person versus feeding everyone in the U.S.” The research found that cutting out animal protein would increase nutrient deficiencies that have been associated with certain health risks, like cardiovascular disease.

When Mic contacted PETA for its perspective, media liaison Catie Cryar noted that because Hall and her co-author work in the meat and dairy industries, “their findings should be viewed with skepticism.”

“More people than ever are going vegan,” Cryar said in an email.

Hall’s study also looked at the impact nationwide veganism would have on the environment, as animal agriculture and consumption are major contributors to greenhouse gas emissions. The researchers estimated that moving entirely to plant-based foods would ultimately decrease total greenhouse gas emissions in the U.S. by 2.6%, which accounts for the emissions that would be contributed by additional crop-only farms.

This reduction isn’t as significant as one would hope.

Crops also emit greenhouse gasses.
Crops also emit greenhouse gasses. BlueRingMedia/Shutterstock

These findings don’t suggest veganism doesn’t help the planet or certain people, only that it’s not a blanket solution. “If we want to grossly change the food system, we need to evaluate what the direct and indirect effects will be on our food supply, environment, etc.,” Hall said in an email.

A different study, published in the journal Elementa in 2016, found that vegan diets aren’t the most sustainable option. This study found that eating entirely vegan wastes available land that could otherwise be used to feed more people with vegetarian or omnivorous foods. In other words, the vegan diet does’t use all the resources the current landscape of the environment provides, Quartz reported.

A chart from ‘Quartz’ depicts results from a study published in Elementa, which found that eating fewer animal products will increase the number of people who can be supported by existing farmland — but that eliminating animal products entirely isn’t necessarily the answer.
A chart from ‘Quartz’ depicts results from a study published in Elementa, which found that eating fewer animal products will increase the number of people who can be supported by existing farmland — but that eliminating animal products entirely isn’t necessarily the answer. Quartz

The answer for eating sustainably is not crystal clear — and it’s certainly not as simple as prescribing veganism for all. As Hall put it:

We need to work through the puzzle of how we meet people’s nutrient and other needs that are met by agriculture, what the land and resources in different geographic areas will support, risks (for farmers to earn a living, water availability, for crop failures, for growing a crop and what portion is wasted, for potential to meet or not meet the population’s needs in any given year), etc.

While Hall’s study looked at an extreme — what would happen if all 325 million Americans ditched animal products — other research shows that to shield the planet from the most detrimental impacts of climate change, it’s imperative the world consumes less meat and dairy. A 2014 study published in the journal Nature revealed that the projected 80% increase in global greenhouse gas emissions from food production can be avoided if we follow a mixture of Mediterranean, pescatarian and vegetarian diets globally, CNN reported.

“We all need to check ideologies at the door as we seek real, practical solutions,” Hall said.

In simpler terms? Realistically saving the world is much complex than going vegan.