I wan't to scientifically determine the extent of an individuals purchasing choices and other legal actions have on supply and demand in any given industry.

Every dollar we spend is a vote for what we believe in, but do we each have a measurable effect? Is our money, our power?

Specifically I'm interested in an individuals effect on supply and demand within the industries of food, drugs, fuel, oil, chemicals, ammunition, ect.

I have eaten a vegan diet for the past 3-4 years for 1. my own personal benefit, 2. human ethics, and 3. civil and environmental sustainability. A plant based diet requires several times less land, fresh water, and grain than a diet containing even small amounts of animal products. This should logically suggest that every person in a 1st world economy has the power to personally save several human lives from starvation through simple processes and or lifestyle changes relating to what food they do and or don't buy for themselves.

Are there any studies or researchers that can show objectively what kind of impact individuals have on supply, demand, and the growth or regression of an industry or practice within the industry(such as livestock breeding, and the purchasing of grain for those livestock)?

As I said, even studies involving, fuel, oil, ammunition, chemicals, anything not fully reusable, is of interest to me.

If you cannot find or do not wish to bother looking for such research, what is your own personal opinion, and why? What is an individuals effect on supply and demand?

http://news.cornell.edu/stories/1997/08/us-could-feed-800-million-people-grain-livestock-eat

http://www.worldwatch.org/files/pdf/Livestock%20and%20Climate%20Change.pdf