Black and white thinking may hinder one’s ability to maintain a healthy weight

13 October 2015

Researchers from the Wageningen University in the Netherlands found that thinking in black and white terms when it comes to food (e.g. thinking of foods as either “good or bad”) can partly explain why the tendency to consciously control food intake is associated with more weight regain. People who follow a rigid “all or nothing” diet approach may be more likely fail to stick with their diet and tend to regain weight in the long-term.

Maintaining a healthy body weight is a challenge. Controlling food intake (dietary restraint) is a good strategy to lose weight, but its effect is often lost with the weight regain after having stopped dieting (also known as the yo-yo effect). Whether a dieter is successful in maintaining the weight loss or not is related to the form of dieting. There are two sorts of dietary restraint, the rigid and the flexible restraint. The rigid restraint is characterized by a strict, rule-based approach. If rigid dieters violate their dieting rules even in a minor way, their “all-or-nothing” attitude might lead them to abandon the diet completely for a while and overeat. The flexible restraint, by contrast, allows fatty or sweet foods once in a while. Consequently, people who have more flexible dietary rules seem to be more successful in maintaining their weight.

The style of dietary restraint might be linked to the general way of thinking. In particular, the tendency to think in extremes, e.g. to think of something as “good or bad” or “healthy or unhealthy”, might play an important role. This mind-set can be a general personality trait or mainly related to food and diet. The researchers in the current study hypothesised that this black-and-white thinking, both in general and specific to food and diet, explains the relationship between dietary restraint and weight regain.

In the present study, 241 mainly female participants, aged between 15 and 74 years, completed a web-based questionnaire. The tendency for both general and eating-specific thinking was assessed with statements such as “All questions have either a right answer or a wrong answer” or “I view my attempts to diet as either successes or failures”. Based on questions on their eating behaviour, the participant’s tendency to restrict food intake for bodyweight reasons was measured. Further, participants who reported having lost weight during the preceding five years were classified as “weight regainers” if they had regained 4 kg or more.

Participants who were prone to think in black and white terms in general were more likely to think in black and white with regards to food and diet. This was, in turn, significantly related to a higher tendency to restrict food intake for weight reasons, irrespective of whether participants were currently on a diet or not. Participants who tended to restrict food intake for weight reasons were considerably more likely to be “weight regainers”, and this relationship was found to be based on the tendency to think in black and white about food and dieting.

These results support the view that a rigid dietary approach, which may be linked to a black and white attitude to food, is related to weight regain. However, this study was based on an online survey in Dutch, and participants were mainly recruited through a mailing list for people who are interested in scientific studies, as well as via Facebook and Twitter. As a consequence, males, older people, and people with a lower educational level were underrepresented. Further, weight loss and regain were assessed in retrospect and through self-report, and no distinction between voluntary and involuntary weight loss was made. Thus, the results cannot be generalised to the whole population.

The authors conclude that a simplified way of classifying food into “good” and “bad” may get in the way of maintaining a healthy weight. A more flexible approach to diet, now and then allowing for fatty or sweet foods without classifying them as “bad”, seems to be the better alternative.

For further information, please see:

Palascha A, van Kleef E & van Trijp HCM. (2015). How does thinking in Black and White terms relate to eating behavior and weight regain? Journal of Health Psychology 20(5): 638–648. DOI: 10.1177/1359105315573440