Thomas gained a lot of weight because he was eating too many sweets. A psychologist suggested to Thomas that he pair the pleasant taste of sweets with the taste of something he finds unpleasant. So, Thomas put broccoli, which he hates, in his ice cream, cake, and pie. He now feels nauseated at the sight of dessert and avoids eating it. This technique is known as

Aversion therapy borrows ideas from classical conditioning. An undesirable behavior is paired with an undesirable stimulus. The undersirable stimulus is the brocolli, which reduces his behavior of eating sweets.