Spurlok's message about fast food is that it is the reason why people (specifically Americans) are so fat.
He tries to prove his message's validity by conducting an unscientific experiment using himself as the subject of the experiment. He also set different rules which he followed throughout his experiment, as well as including facts, examples and explanations which help the audience picture the effects of consuming fast food.
As a director he uses interviews from experts in nutrition and obesity-related experts to make his message more believable.
The flaws that I see in his strategy are:
-He doesn't include the other side of the story. For example from people who work at McDonalds or other fast food companies.
-He didn't include some of the reasons why some people eat fast food everyday- Lack of money coud be an influential factor.
