It just doesn't seem fair, scientists say diets lead to spending more on impulse purchases

Dieting: Good for your health, potentially bad for your pocketbook

If you go on a diet, you are more likely to make more impulse purchases according to a study from the March issue of the Journal of Consumer Research.

Researchers explored the effects of mental self control (such as the type that one needs to diet) in the following experiment.

...a group of participants to write down all their thoughts for six minutes. Another group was told that they should also write down all their thoughts – with one exception. The participants were told that if they thought of "a white bear" they were NOT to write it down, but instead to place a check mark at the side of their paper.

The participants were then told that they were taking place in an unrelated study and given $10 to spend on items from the college bookstore. They were told that whatever unspent money was theirs to keep.

Even a small regulatory exercise – the attempt to suppress an innocuous thought about a white bear – caused the participants who had exercised mental self-control to spend and buy more. Those who had just tried to control their thoughts spent an average of $4.05. Those who had been free to write whatever they wanted spent an average of $1.21. Participants who had previously been asked to exercise self-control also bought twice as many items on average as members of the unregulated group.

The researchers concluded that people need self-regulatory resources to resist impulse buying temptations, and that these resources can be depleted by prior self-control efforts. They also noted that "people should avoid shopping on days when they have earlier exercised great self-control or when starting a new self-improvement program, such as a new diet."

As we were going to print (metaphorically) I noticed that Gretchen Ruben is blogging on the same data from a slightly different angle. A worthy read.