This is a double-bluff that I used as a warm-up last year:
Question: True or False, eating chocolate can cause acne?
Surprisingly it may be true.
Spots are certainly not directly caused by what food one eats, they erupt due to overactivity in the glands which secrete oil onto the skin. This oil clogs the pores which give bacteria an excellent environment to grow.
So what does chocolate have to do with this? Well the overactivity is often caused by increased testosterone (one reason why teenage boys have worse acne than girls) and recent studies have shown that increased dairy products may lead to increases in testosterone. So despite many dermatologists claims to the contrary, eating lots of milk chocolate may indeed increase your chances of getting acne.