Restrictive dieting may worsen mental health, large US study finds

Severe calorie-cutting could have adverse effects on mental health, according to a new study based on US data, CNN reported.

Published in BMJ Nutrition, Prevention & Health, the research assessed over 28,000 adults and found a link between restrictive diets and increased symptoms of depression, especially in men and people with higher BMIs.

Participants reporting low-calorie diets experienced more signs of depression. Diet quality was also a factor: people who consumed more ultraprocessed foods, sugars, and saturated fats reported worse symptoms, while those eating Mediterranean-style diets fared better.

“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.

The study’s design limits its conclusions to associations rather than causation. “I could think I am on a calorie-restricted diet when in fact I may be in a calorie surplus,” said Dr. Kary Woodruff, who was not involved in the research.

Other studies have produced different outcomes. Some have found that supervised calorie restriction improves mood. “These findings might reflect that unsupervised dieting, which can produce nutritional deficiencies, might not be good for depressive symptoms,” said Dr Johanna Keeler, who coauthored a 2023 paper on the subject.

Severe calorie cuts may also lead to nutrient deficiencies and disrupt body functions, contributing to fatigue, sleep problems, and poor concentration. “Focusing on following a healthful eating pattern that supports mild to moderate caloric restriction may improve depressive symptoms and mood,” said Woodruff.

Experts emphasise balanced eating over drastic restrictions. “Start by looking at your meals,” said dietitian Natalie Mokari. “Does your plate have a protein, carbohydrate, healthy fat, and some fibre and nutrients through fruits and vegetables?”

Bhat noted the need for personalised plans that account for psychological wellbeing. As Woodruff added: “Consider working with a registered dietitian to understand what a healthful dietary pattern can look like for you.”