Study links extreme calorie restriction to worsening depression symptoms

A new study suggests that excessive calorie restriction may be linked to heightened depression symptoms, particularly among men and those with higher body mass indexes, CNN reported. 

Published in BMJ Nutrition, Prevention & Health, the research analysed data from over 28,000 adults via the National Health and Nutrition Examination Survey.

Researchers found that people who adhered to low-calorie diets were more likely to report depressive symptoms. The impact appeared more pronounced in individuals already considered overweight. 

The study also highlighted the importance of diet quality. Diets high in ultraprocessed foods, refined carbohydrates, and processed meats were associated with greater depression symptoms, while those following a Mediterranean-style diet reported fewer mental health issues.

“The findings suggest caution with overly restrictive or unbalanced diets, particularly for people already experiencing weight-related stress or challenges,” said lead author Dr Venkat Bhat of St Michael’s Hospital and the University of Toronto.

However, the study could not establish a direct causal link. Dr Kary Woodruff, who was not involved in the research, noted, “I could think I am on a calorie-restricted diet when in fact I may be in a calorie surplus — there’s no way to verify participant’s calorie-restriction status.”

Past studies have linked medically supervised calorie restriction with improved mood. “These findings might reflect that unsupervised dieting, which can produce nutritional deficiencies, might not be good for depressive symptoms,” said Dr Johanna Keeler of King’s College London.

Experts say extreme calorie restriction could impair sleep, concentration, and physical health, potentially worsening depression. “Focusing on following a healthful eating pattern that supports mild to moderate caloric restriction may improve depressive symptoms and mood,” said Woodruff.

Personalised guidance is key, according to Bhat, who recommends dietary changes that consider both mental and physical health. 

Dietitian Natalie Mokari adds: “Start by looking at your meals. Does your plate have a protein, carbohydrate, healthy fat, and some fibre and nutrients through fruits and vegetables?”