Research Confirms Caloric Restriction Linked to Increased Depression Risk

Dieting can often be a challenging and unenjoyable process, particularly when one trades indulgent snacks for healthier options like carrot sticks.

A recent study has shed light on the connection between caloric restriction and an increased risk of depression, with findings suggesting that men may be more affected than women.

The research team from the University of Toronto analyzed data from 28,528 adults across the United States over a decade, focusing on their dietary habits and mental health outcomes through surveys and clinical assessments.

Participants who adhered to low-calorie diets reported higher levels of depressive symptoms, including fatigue, concentration difficulties, and a diminished interest in activities.

The study’s authors posited that the relationship between calorie reduction and depression might stem from potential “nutritional deficiencies” associated with insufficient protein and vitamins, leading to impaired brain function and lower moods. They also suggested that inadequate weight loss or fluctuations in weight during dieting might exacerbate depressive feelings.

Interestingly, the effects were notably more pronounced in men, possibly due to their increased nutritional demands and a tendency to struggle more with dieting compared to women.

Published in BMJ Nutrition Prevention & Health, the researchers concluded that restrictive diets are uniquely associated with significant increases in depressive symptom scores relative to those not engaging in dieting.

Adequate brain health relies on sufficient glucose for energy and omega-3 fatty acids for optimal functioning, and restrictive dieting may impair brain functionality. The researchers observed that both calorie constraints and obesity often lead to nutritional inadequacies and physiological stress, potentially heightening depressive symptoms.

Using the PHQ-9, a standardized clinical survey for measuring depression, nearly 10% of participants reported following a calorie-restricted diet. Those individuals, on average, exhibited scores that were 0.29 points higher on the depression scale compared to non-dieters, with men experiencing more severe symptoms.

The researchers theorized that biological men often have higher caloric requirements, making restrictive diets more challenging and possibly influencing their mood differently than biological women. They noted men’s preferences for richer, often fast-food meals, which might lead to a more pronounced impact on mood when dieting.

While this study is observational and does not establish causation, experts emphasized the need for further research to better understand the connections between dieting and mental health.

Professor Sumantra Ray from the NNEdPro Global Institute for Food, Nutrition and Health commented that the findings contribute to the growing body of evidence linking dietary patterns with mental well-being, raising critical questions about the implications of restrictive diets low in nutrients beneficial for cognitive health — such as omega-3 fatty acids and vitamin B12 — on the development of depressive symptoms.

She highlighted that while the effects noted are small, the need for more rigorously designed studies to investigate the relationship between dietary practices and depression remains essential.