What Does Your Diet Say About You?

Research finds that those who follow different diets may differ psychologically.

Posted Jun 24, 2019

Source: Bark/Flickr

Do people who adhere to different diets also differ from each other in key psychological ways? This was the question of a new study led by psychologist Rebecca Norwood of the University of Queensland. While research has focused on psychological factors that are associated with weight-loss diets, Norwood and her collaborators noted that there has been less focus on how these factors correlate with other types of dietary patterns. The team argues that uncovering these relationships could shed light on the challenges that often accompany weight-loss diets and provide new insights into the psychology of food consumption.

In order to explore the correlations between diet and psychological characteristics, Norwood and her team began by recruiting participants and asking about their dietary patterns. They provided seven options: "vegetarian," "vegan," "paleo," "gluten-free," "weight-loss diet," "unrestricted diet," and "another specific restricted diet." Participants were also asked how long they had followed this pattern, and whether they had any medical conditions.

Participants also completed two sets of psychological measures. The first set inquired about eating attitudes and behaviors, with questionnaires that probed about disordered eating behaviors, self-control, emotional eating, and food cravings. Participants were also assessed for self-efficacy (how confident they felt about sticking to their dietary plan for the next 90 days), dieting intentions (a prediction of immediate-future efforts to change eating habits), and dietary motivation (i.e., a measure that delves into food choice, in which participants rated how important the factors of health, mood, convenience, sensory appeal, natural content, price, weight control, familiarity, and ethical concern were in their food choices). The second set of measures pertained to well-being. Respondents completed measures that assessed their levels of self-esteem, depression, anxiety, stress, and the extent to which they felt negative emotions.

What did the researchers find? The participants broke down into five groups of dietary patterns, and there were significant differences between them on certain psychological characteristics:


The investigators found that, overall, this group had a decreased presence of medical conditions and showed good psychological health. They reported generally positive eating attitudes and behaviors, especially when it came to dieting intentions, eating disorders, food cravings, self-esteem, and self- efficacy.


Of all the dietary groups, this group had the largest number of participants. The authors posit that this may be due to their passionate views on food consumption and that this study presented an unusual opportunity to share them. The findings revealed that this group showed higher levels of diet self-efficacy, which reflects confidence in being able to stick to a diet. Vegan participants were also somewhat more psychologically healthy by comparison to the other groups, with particular respect to eating disordered symptoms, decreased levels of emotional eating, and dieting intentions. Moreover, they were lower on both stress and weight-control motivations. Moreover, vegans showed lower motivation in their food choices on the factor of familiarity by comparison to the other groups.


This group was the second oldest and second heaviest of the groups (after paleo) in this study. And in keeping with expectations, they had the most diet-related medical issues. The majority of respondents in this group had been diagnosed with celiac disease or suspected that they had it—or had a gluten allergy or intolerance. Perhaps unsurprisingly, this group reported elevated levels of stress.


This group was the oldest one in the study. They had the highest rate of obesity, and 37 percent of paleo participants had a diet-related medical issue. It follows, then, that they had the highest levels of health-related motivation for following this diet, and the highest motivation to eat natural foods. The paleo group also showed good psychological health overall, as well as good eating attitudes and behaviors. They exhibited greater self-control and self-esteem and showed lower negative affect and depression by comparison to the other groups. Of note, paleo participants were the least likely to be motivated by weight-control to follow this diet.

Weight loss 

The participants in this group struggled more than those belonging to the other diet groups. More specifically, they had the highest levels of eating disorder symptoms, food cravings, emotional eating, and negative affect. They also had comparatively lower self-control and self-efficacy. These findings remain consistent with previous research, which has found that this diet pattern is associated with depression, binge eating, and loss of control over eating behaviors. And boosted levels of emotional eating and negative affect, as well as lower levels of self-esteem and self-efficacy, are related to more food consumption, more binge eating, and more unsuccessful weight loss outcomes. That said, the investigators maintain that there is a crucial difference between supervised and unsupervised weight-loss diets. Burgeoning research demonstrates that “effective, assisted weight loss” is related to better mental health and lessens disordered eating. In other words, the weight-loss diets that are often unsuccessful appear to be the ones where people go it alone.


The psychological characteristics of people consuming vegetarian, vegan, paleo, gluten free and weight loss dietary patterns. R Norwood, T Cruwys, VS Chachay, & J Sheffield. Obesity science & practice 5 (2), 148-158