I have found that most restaurants don't really even care if you do this as long as you are purchasing some food. I always bring my own avocado with me when I eat out because the restaurants always charge at least double of what an avocado sells for on the open market. Shopping Seek out your closest health food store for items that you may not find in a supermarket such as, rice and soy milks, garden hotdogs and burgers, organic produce, etc. Look out for hidden animal-products like casein. And try to stay away from hydrogenated oils.
Hydrogenated oils act like animal-fats in the body and can contribute to the clogging of arteries.
Read as much as you can on the subject. I recommend the following books for someone just starting out. Inc. All Rights Reserved.