Even if you are not looking to go fully vegan, doing it a few days a week will not only improve your health—it will also make a huge environmental impact. If we all did this, even on a gradient, we would greatly change our environment. For example, replacing a burger with an alternative saves about 660 gallons of water, according to environmental documentary Cowspiracy. That’s a lot of water. So how do you start? I did it cold turkey, but most people I know like to cut things out little by little.