Two Cornell University researchers in the department of psychology and nutritional sciences (interesting combination) released a very influential review article in the journal Public Health Nutrition that makes the case that people are socially conditioned to eating habits they have no personal control over.

Americans “hold the belief that the decision as to what and how much to eat is determined by their own free will,” the researchers begin. “The evidence demonstrates, however, that this is not true.”

The research was led by David Levitsky, now Professor Emeritus of Nutritional Sciences at Cornell Human Ecology. Dr. Levitsky provided an interesting statement summarizing his work at Cornell:

I believe that the fundamental premise underlying our understanding of increasing body weight is wrong — that our eating behavior is not driven by physiological signals [that] act to keep our body weight (fat) constant (set-point). I believe that we are driven more by ubiquitous environmental food stimuli for us to consume slightly more calories than we expend.

Dr. Levitsky places much of the blame for obesity on what he calls “food primes” and we call cues. He explains the concept:

Variables such as portion size, variety of foods offered, fat content of the diet, the number of people eating, the location where eating occurs and even watching food advertisements act as ‘food primes’ causing individuals to increase their energy intake.

Dr. Levitsky feels Americans suffer from the delusion that they control their weight with their own free will. Therefore, he says, they willingly diet to reduce their weight. Nearly half of all U.S. women and one-third of U.S. men were “on a diet” at the time of publication in 2011.

However, writes Dr. Levitsky, “The evidence is extraordinarily clear: losing weight by dieting is futile.” The figures he offers are fairly convincing:

• We continue to gain weight despite a third of the U.S. dieting.
• Weight reduction programs have a dropout rate of 77% in the first year.
• For those who don’t drop out, weight loss averages 10kg in the first year.
• They regain 6kg in the first year after therapy is completed.

The researchers report on the fascinating results of “replacement meals,” pre-packed liquid or solid meals that contain far fewer calories than a typical meal. They have been shown to reduce weight by 10kg after six months and keep it off for years.

What’s so interesting is, it doesn’t matter whether the meals are high in protein; what matters is “that free choice to determine what and how much food to eat is removed from the individual.”

The researchers also praise the effectiveness of weight loss groups for increasing the social pressure to resist eating. In particular, Dr. Levitsky is a huge fan of the weigh-in, a standard feature of weight loss apps. The weigh-in is “a negative food prime,” writes Dr. Levitsky, which can be harnessed to reduce “age-related weight gain.”

Dr. Levitsky puts himself in the camp of the “environmental determinists” who “believe that human eating behaviour is determined more by the environment in which humans live than by the biological mechanisms underlying the control of food intake.”

We are tremendously influenced in our eating behavior by cues such as the amount of food on the plate, the size of food and beverage containers, and our estimates of how much everyone else is consuming. Average portion sizes have increased more than 25% since 1980, in both restaurants and at home.

Not only are portions bigger, they contain more variety. When people have more foods to choose from, they eat more. For example, researchers say that people will eat more M&Ms candies on average the more colors they have to choose from. Or they will order starters as well as a meal and a side dish at a restaurant.

Is obesity a social disease, then? “Our eating behaviour is very sensitive to others in our environment. Considerable data have been published demonstrating that the more people we eat with (particularly when we are familiar with the people with whom we are eating), the more we consume,” the researchers write.

Furthermore, the researchers write that if people connect non-food cues with eating behavior, they can be bombarded with eating cues without even realizing it:

Any environmental stimuli that are associated with food or eating have the potential to elicit feeding, whether people are conscious of them or not.

“These food primes are so powerful,” the Cornell researchers write, “that the only way most people can lose weight is to be removed from eating ‘freely’ in this environment.” On the positive side, an ability to maintain dietary restraint combined with daily weight measurement are “characteristics of successful weight restrainers.”

“This increase in dietary restraint confirms the necessity of increasing awareness of the environmental cues that seduce us to eat,” write the researchers. We have only scratched the surface of this subject, so stay tuned for more on the social nature of addiction here at AddictionNews.

Written by Steve O’Keefe. First published November 6, 2026.

Sources:

“Free Will and the Obesity Epidemic,” Public Health Nutrition, September 19, 2011.

“Social and Structural Determinants of Health and Social Injustices Contributing to Obesity Disparities,” Current Obesity Reports, June 15, 2024.

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