When researching food related issues, you need two things before you can get started.
Don't worry if you don't know everything about your topic yet, or if it seems too broad a topic to cover in your paper. Your initial search with a term like "Obesity" may lead you to more specific terms like "Childhood obesity," which you can pair with "fast food" or "soft drinks" and build a more specific search.
When you find sources that seem relevant, click on the titles to see a summary, also known as the abstract.
If this source still seems useful for your project, go to the right side of the page and use the retrieval tools like "Add to folder" to mark it, or "Permalink" if you want to send the source URL to yourself or a classmate. "Cite" displays all of the citation information you should need to credit the source in a project.
You can email a single source, or you can add several to a folder and send them all at once, with citations, to your email address. Simply click on the Folder at the top of the page to view everything you have marked, and then E-mail.