Try searching in the library catalog for books about health and social issues using broad terms first, then narrow down your results.
For example, you may want to try multiple combinations to find the best terms, as every combo will result different results:
school lunch and health
school lunch and nutrition
school lunch and obesity
Use a scoped Google search to limit your results to .org/.gov/.edu websites.
For example, to find governmental websites about alternative medicine, try searching:
alternative medicine site:gov
To find statistics from think tanks about the Affordable Care Act, try searching:
affordable care act statistics site:org
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