One who only partakes of food that is "sustainably sourced:" for example, vegetarian fare, sustainably caught seafood, or sustainably raised, or game, meat. While a vegetarian meal is Sustainatarian, not all Sustainatarian meals are meat-free;
A dietary preference as described above.
As a Sustainatarian, Julie would eat wild-caught salmon but not farm-raised fish.
Broadly speaking, the term sustainatarian applies to decision-making based on principles of environmental sustainability and fairness to both humans and animals.
Different than a vegetarian (who may eat factory-farmed dairy), or a vegan (who will not eat animal products of any kind) a "sustainatarian" is a person who eats a mostly plant-based diet with occasional sustainable meat, meaning that it is locally and humanely raised. The term also refers to buying fair trade, organic, recycled, reused and/or reusable food, clothing and consumer goods wherever there is a choice.
"Being a strict sustainatarian, I only buy beef if I can get it from pastured cows raised comfortably on a local small-scale farm".