Anyone who engages in a lifestyle not promoted by the mainstream of culture will face resistance and fear from others. If one’s choices promote a happy, healthly lifestyle, the example will be noticed and defensive words unnescessary. I would suggest dropping all references to your lifestyle as ‘frugal’, ‘inexpensive’, ‘less wastefull’, etc. These terms will most likely provoke fear and anger in those committed to high consumption of resources. Your choices can exist as your choices without a label to defend them. When challenged on a specific issue, one can gently question “Why do you think …..?” Allow them a full response and then follow with a “Thank you” and nothing more. Hopefully, this will demonstrate repeatedly that you feel secure enough in your choices to be concerned that they have the opportunity to respectfully express an opinion which you can respectfully accept as THEIR opinion. I don’t believe you want to make enemies of these people, but to feel secure and respected in your own choices. Show them how to do it!