Restrained eating

Welcome back. Today’s lecture will cover the cognitive topic known as restrained eating behavior. The literature and research on restrained eating is immense and has already begun in the 1970s. Restrained eating refers to the conscious effort to restrict one’s food intake by avoiding or limiting certain food groups or by eating less, or a combination of both in order prevent weight gain or to lose weight. Restrained eating is sometimes also described as “chronic dieting” Hovewer, early laboratory studies have demonstrated that participants categorized as restrained eaters increased rather than controlled their intake of palatable food in response to high calorie preloads or negative mood induction.

This phenomenon is considered a cognitive one because what matters is not whether restrained eaters actually restrict their diets but whether they think that they did. Let me give you an example Already in 1975, Herman and Mack published a study in the Journal of Personality that described an experiment randomly assigning participants to one of three groups. One group received a preload in form of a milk shake, the second group received two milk shakes as a preload and the third group received no preload. All groups were then asked to taste and evaluate three different flavors of ice cream. In addition, participants filled out a questionnaire measuring restrained eating behavior.

The results showed that unrestrained eaters – those that weren’t dieting - ate less ice cream after both milk shake preloads adjusting for their intake while restrained eaters ate more ice cream after the milk shake preload. Researchers explained this effect as a loss of control caused by non physiological stimuli resulting in disinhibition and overeating. These stimuli were thought to undermine cognitive control. So, restrained eating is the attempt to control food intake but whether one succeeds or not seems to depend on various factors. As a matter of fact, the group of restrained eaters are not homogenous in regards to their vulnerability to disinhibition, some can successfully restrain their intake, while other fail and even overeat.

For over 40 years now the postulated restraint theory has been examined. Confirming and contradicting results were found and discussed. Given the time limit on the lecture, I want to mention only some of the factors that have been investigated and seem to impact restraint or more precisely seem to inhibit the cognitive control. Which factors appear to play a role in the disinhibition of cognitive restraint?

Let’s talk about some interesting ones: first, highly palatable food (also attractive

smell, sight, etc.): Experimental studies have found that restrained eaters eat more than unrestrained eaters when they are exposed to highly palatable food, attractive food smells or even simply the sight of food. These factors seem to encourage overstepping the personally set intake boundary of restrained eaters.

second environment (such as food related TV advertisements, food labels : Other external factors such as food related television advertisements or labels indicating healthy or low calorie food products are other variables that appear to have the potential to disinhibit restrained eaters’ control of food intake.

negative emotional state: I am sure you remember the lecture on how emotions might change our eating behavior. In that lecture I also mentioned how negative emotions can cause restrained eaters to overeat. This effect has been observed in studies where a negative mood was induced by -for instance- showing a sad movie. So being sad seems to increase the likelihood for restrained eaters to lose their cognitive restraint. One possible explanation is that cognitive efforts may be reduced by emotions and as a result restrained eaters might increase their food intake. Subjective opinion on personal body weight

or calorie content of the offered food: This is an interesting effect. Studies found that when people were asked to step on a scale that actually did not show the actual weight of the participant but showed about 2 kilograms more restrained eaters tended to overeat while this effect was not observed in unrestrained eaters. The same effect was observed by giving an incorrect calorie content of offered foods in an experiment. So, for restrained eaters, what was told appeared to be more of a determining factor than what the person felt or thought she or he knew. fifth observed or unobserved by experimenter.

As a last influencing factor I want to mention an experiment where restrained and unrestrained eaters where asked to consume candy after a milkshake preload manipulating the availability of a wastebasket for the disposal of candy wrappers. The participants either had to leave the candy wrappers on the table which was considered public attention or they could put them in a wastebasket, which was considered self-attention. The results showed that restrained eaters ate considerably more candy when they could throw the wrappers away while this effect was not observed in unrestrained eaters. As you can see, many factors possibly affecting restrained eating have been observed but it is important to point out again that many studies also show contradicting results.

Therefore, we need to discuss some limitations and concerns The first issue is that Restrained eating is being assessed by self-report questionnaires.

Participants are asked questions like: “Do you eat less to avoid weight gain?” or “Do you try not to eat between meals?” But we are not really good at assessing our own behavior. We don’t remember well and we tend to not do what we say we would do in actuality. Generally, in research, it is always better to have an objective measure instead of self-reports about a behavior. Another issue with these questionnaires is their way of categorizing participants into the group of unrestrained and restrained eaters.

Some questionnaires do not have a cut-off point but split the study sample based on their questionnaire scores in the middle with participants with high scores in the group of restrained eaters and participants with low scores in the group of unrestrained eaters. So it depends on your sample type what is considered restrained or unrestrained eating. As an example, if you study a group participating in a weight loss program your scores on the restrained scale will likely be generally higher among this study sample compare to group of students. The second issue is that the experimental set-up does not apply in real world.

The large majority of the conducted study on restrained eating are experimental studies And there seems to be something very different in participants’ eating behavior whether they attend an experiment compared to their every day eating behavior. Epidemiological and field studies provide little evidence for the idea that restrained eating causes disinhibited eating patterns. Therefore, some scientists argue that restrained eating co-occurs with disinhibited eating and is not necessarily the cause of it but that restraint is rather a marker for overeating tendencies. In summary, restrained eating is the conscious intention to limit and control food intake in order to lose weight or to prevent weight gain Whether somebody succeeds in following this intention depends on many factors.

how applicable all the conducted experimental studies are for the real world eating behavior is still being discussed. That was it for today, and I hope you can watch our next lectures.