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The Limits of Self-Control

Want to quit smoking? Pick up a chocolate habit.

Want to quit smoking? Try picking up a chocolate habit.

Or at least, give yourself permission to indulgence in whatever foods you find most tempting. A new study by UC San Francisco researchers Dikla Shmueli and Judith Prochaska shows why it's a bad idea to try to change too many health behaviors at once.

101 smokers were invited into the laboratory for a study on food temptation. They were told that the study was a challenge of sorts--researchers were interested in whether or not participants could resist a range of snacks, from raw radishes to freshly baked brownies.

Participants were then put in a room alone with a randomly-assigned food (healthy vegetables or more tempting baked goods). Their assignment: do not eat the treat!

The researchers made sure participants got the full effect of the temptation. For five minutes, they sat and stared at the treat. Every fifteen seconds or so, a chime rang, indicating that the participant should get closer to the plate, lift it up, and smell the food. They were also asked to really think about the food and their desire to eat it. Short of licking the chocolate frosting, this is about as strong a sensory temptation as the researchers could have set-up.

After this test of willpower, participants were given a ten-minute break so the experimenter could set up the next phase of the study. Participant could wait in the lobby or go outside during the break.

What the researchers really wanted to know: Would resting sweets make smokers light up during a 10-minute study break?

After the break, the researchers used a Smokerlyzer to test the participant's breath for evidence of smoking. The results: Participants who had resisted dessert were more likely to smoke during the break (53%) than those who had resisted the less appetizing radishes (34%).

Why? It could be that a craving is a craving, and if you don't give in to one, you'll be doubly attracted to the next. Or perhaps resisting temptation is a form of stress, and stress triggers the need to smoke. The researchers cite Roy Baumeister's theory on the limits of self-control as a likely explanation. You only have so much self-control before your willpower is exhausted. When your willpower is weakened by resisiting one temptation, you're more likely to succumb to the next.

These findings are consistent with other research on trying to quit smoking. Smoking cessation interventions that include nutritional counseling or dieting plans have higher failure rates than programs that only focus on quitting smoking. While trying to overhaul your lifestyle all it once may sound appealing, it isn't sustainable, especially in the early stages when cravings for cigarettes and food are at their worst.

The bottom line: when you're trying to make a difficult change, save your strength for what matters most. If both a cigarette and candy bar are calling your name, let the candy bar sweet talk you into indulgence. You can kick that habit later. Or maybe not-last I heard, there was a new study showing that chocolate is good for you. Plus, gaining a few pounds might help you live longer.

Study cited: Shmueli, D. & Prochaska, J.J. (2009). Resisting tempting foods and smoking behavior: Implications from a self-control theory perspective. Health Psychology, 28(3), 300-306.

More from Kelly McGonigal Ph.D.
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