Researchers have discovered a way for people to eat less: imagine eating. Better than any diet pill, workout routine or all-cabbage-all-the-time regimen, simply thinking about eating food will make a person eat less.

The work is based on a process called habituation — a phenomenon that decreases the responsiveness to and motivation for obtaining food. (For example, the first bite of a hamburger or candy bar is often more exciting to the brain than the tenth bite.) Satiety cues do not always reach the brain fast enough to stop consumption when the body is full, so the brain relies on outside stimuli and psychological processes, such as habituation, to slow eating.

Authors of the latest study hypothesized that imagined consumption could elicit habituation the same way as actual consumption. In the study, published in the December 10, 2010 issue of Science, researchers showed that people who visualized every chew and swallow of food ate less than people who imagined doing other activities.

The study reports the results of five separate experiments, each including approximately 50 to 60 participants, most of whom were college students, but some experiments included a larger sampling of American adults. In each of the experiments, groups of participants were asked to imagine eating a food (usually candy or cheese) many times or a few times or completing a mundane task (putting quarters in a washing machine) many times or a few times. They were then given the opportunity to actually eat the imagined food. The people who pictured eating the food many times consumed less of that food compared to people who imagined eating a small amount of that food, eating another food, or doing another activity.

The results were not affected by hunger or by like or dislike of the particular food. Also, imagining the food did not decrease the enjoyment of consuming the food in these experiments. As the authors postulated, imagination appears to have the same effect on habituation to food consumption as actually eating the food.

Many factors influence habituation, in addition to imagination. Notably, variety in the diet reduces habituation. The rate of habituation is inversely proportional to calorie intake, and obese people habituate slower to food stimuli than lean people. Memory also influences habituation. Plus, individual factors and other behavioral and psychological responses determine the rate and extent of habituation. Accordingly, the latest research needs to be expanded to include larger, more diverse populations in order to be applied to real-world settings.

Visualization is an important psychological tool, with coaches routinely telling players to visualize winning the big game, therapists advising patients to picture where they want their life to go, and caregivers recommending that an ill person envision getting stronger and healthier. One would assume that visualizing eating less food would inspire less real-world consumption, but this does not appear to be the case: imagine eating more of the food and make the body think it has already consumed it. While you’re at it, imagine doing the laundry, mowing the lawn, and going to the gym.

References

Epstein LH, Robinson JL, Roemmich JN, Marusewski AL, & Roba LG (2010). What constitutes food variety? Stimulus specificity of food. Appetite, 54 (1), 23-9 PMID: 19765625

Epstein LH, Robinson JL, Temple JL, Roemmich JN, Marusewski A, & Nadbrzuch R (2008). Sensitization and habituation of motivated behavior in overweight and non-overweight children. Learning and motivation, 39 (3), 243-255 PMID: 19649135

Epstein LH, Robinson JL, Temple JL, Roemmich JN, Marusewski AL, & Nadbrzuch RL (2009). Variety influences habituation of motivated behavior for food and energy intake in children. The American journal of clinical nutrition, 89 (3), 746-54 PMID: 19176724

Epstein LH, Temple JL, Roemmich JN, & Bouton ME (2009). Habituation as a determinant of human food intake. Psychological review, 116 (2), 384-407 PMID: 19348547

Morewedge CK, Huh YE, & Vosgerau J (2010). Thought for food: imagined consumption reduces actual consumption. Science (New York, N.Y.), 330 (6010), 1530-3 PMID: 21148388

Myers Ernst M, & Epstein LH (2002). Habituation of responding for food in humans. Appetite, 38 (3), 224-34 PMID: 12071689