If i saw a video ad that shows a man talking about the diet pill he uses while they show that he is not an actor and doesnt read any type of script. This type of advertising technique is called plain folks - "letter B". plain folks type of advertising is commonly used for food and drug type of products.
I think that by using a non actor for a diet pill commercial would help persuade the viewer to get the pill because since the man isn't an actor, it shows that real people use the pill and recommend it.
