You can definitely follow a low-carb, plant-based diet. But it's more difficult than a regular keto diet. Just make sure you stay away from vegetable oils, and that you don't overindulge in starchy plants (such as potatoes or grains). The challenge you'll have on a vegan diet is to get your protein. Vegans often rely on grains for their protein. Unfortunately, those seeds of grass have a lot of carbs, which you can't have on a vegan keto diet.