Food for Thought

Can thinking about eating M&Ms intensely before eating them result in needing fewer to satisfy? The popular wisdom on the matter is that you should try to put those thoughts out of your head to stem the cravings. An exciting new study was just published in the journal Science by Carey Morwedge and colleagues that seems to suggest imagining high-calorie foods before you eat them will result in you eating less of them. Cleverly they took a group of 51 graduate students from Carnegie Mellon University and tested this hypothesis.

The subjects were divided into three groups and asked to close their eyes, concentrate, and imagine a series of repetitive tasks. In one group the students imagined putting 30 quarters in the slot of a coin-operated washing machine then eating 3 M&Ms. In the second group the imagined activities were reversed: M&Ms first, same numbers. The third group was asked to imagine the washing machine again but the change was putting only 3 quarters in, one at a time followed by imagining eating 30 M&Ms in a row.

At the end of the mental exercises each participant was let into a room with a bowl of, you guessed it, M&Ms. How many they ate was measured by weight and the three groups compared. When I asked several of my friends what they predicted was the outcome, nearly all of them said the mental warm-up for M&M eating would increase the number consumed. Not so.

In fact the study subjects were asked if the imaginary food they consumed had diminished their appetite for the hard-shell candies. Participants agreed with most of my friends and said the mental imagery did not reduce their appetite for specific foods. The results of the M&M thoughts versus standard repetitive tasks was striking and significant. People who thought a lot about M&Ms before eating them ate almost half as many as people who thought about putting quarters in a laundry machine.

The effects were specific to the type of food thoughts as well. Imagining cheese snacks going down the hatch did not reduce the consumption of M&Ms. The specific effect is called habituation. Habituation is a quality of the mind that allows it to progressively ignore a stimulus over time. When you first put on your socks and shoes in the morning you are no doubt aware of the feeling of these articles of clothing on your feet. Usually within a brief time the specific awareness of sock and shoe fades. Same for scents, sounds and images. The brain can turn down its focus on any specific stimuli so as not to be drowned in perceptions.

This is part of why novelty, the pursuit of the new, is so compelling. A premium is placed in human development on pattern recognition. Once a specific stimulus or input has been categorized is takes less computational power to manage it. Perception is modularized into units or blocks that can be filed away for later use. I think that the research subjects became weary of thinking about M&Ms and were turned off by the thoughts the same way as if they had eaten them to their fill.

What are the potential implications for recovery from the malady of addiction? Should we be suggesting to our peers in recovery that they spend time thinking about drinking alcohol before going out to a party? Some of the limitations of the study methodology were the research environment itself. People are subject to a diverse array of stimuli and distractions prior to eating a meal or drinking a drink. Further, in the case of mind-altering substance use, the drug certainly has a larger effect on thought processes than the period of prior mental habituation would.

Perhaps that is the mechanism of action in the “alcoholic” mind. It may be that the substance, in this example ethanol, works by directly inhibiting the circuits involved in habituation. The feedback loop is interrupted and the only obvious choice at hand is to have another drink. Conversely, the use of Methadone maintenance treatment probably confers an artificial relief of dysphoria. The presence of methadone or buprenorphine┬áin the brain has been shown to reduce the consumption of other opiates in most people. This further supports the idea of habituation in reducing the drive for drugs.

In recovery circles it is common to hear the idea that when presented with a craving one should “think through the drink.” Colloquially this is taken to mean imagining the consequences of a relapse and eventual return to uncontrolled drinking or drug use. Maybe more fundamentally mechanisms of habituation are in play. Thinking through the drink may scratch the itch enough to keep you from taking one. What do you think?



Category: Current Events, Neuroscience, You Don't Need Rehab

About the Author: Dr. Jason Giles is certified by the American Board of Addiction Medicine and the American Board of Anesthesiology. He is a physician specializing in the treatment of drug, alcohol, and behavioral addictions. He is the founder of Haywire.

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