The documentaries Supersize Me and Aileen: Life and Death of a Serial Killer use different filmmaking techniques to tell different stories. Supersize Me follows a man who eats only McDonald's for a month, using interviews, opinions, scientist interviews and animation clips. Aileen uses old police footage and interviews to tell the story of serial killer Aileen Wuornos. Both target American audiences, but Supersize Me aims for younger viewers while Aileen targets older females. Audience research found most viewers prefer one-hour documentaries and look for interesting subjects and exclusive interviews when choosing one to watch.