• Posted June 4, 2025

How Do Low-Calorie Diets Affect A Person's Mood?

WEDNESDAY, June 4, 2025 (HealthDay News) — Counting calories isn’t simply a bummer, it might actually increase your risk of depression, a new study says.

People on low-calorie diets scored higher for symptoms of depression, compared with those not dieting, researchers reported June 3 in BMJ Nutrition Prevention & Health.

Overweight people and men were particularly vulnerable to the mood changes that come with a low-calorie diet, results show.

“Calorie-restricted diets were associated with higher depressive symptom scores, which contrasts with the findings of earlier controlled studies,” concluded a team led by senior researcher Dr. Venkat Bhat, an associate professor of psychiatry at the University of Toronto.

“Additionally, biological men and overweight individuals appear more vulnerable to the negative effects of restrictive eating,” the team added.

Cutting calories might also rob the brain of nutrients needed to maintain a balanced mood, researchers speculated.

For the study, researchers tracked the health of more than 28,500 participants in the U.S. National Health and Nutrition Examination Survey between 2007 and 2018.

These people all had completed a questionnaire assessing symptoms of depression, and also were asked if they were following any particular diet.

In all, just under 8% of participants reported symptoms of depression.

Researchers categorized everyone based on their dietary pattern, including diets that restricted calories, diets that cut specific nutrients like carbs or fat or diets established to help manage health problems like diabetes or heart disease.

About 87% of people weren’t on any diet at all, while 8% followed a low-calorie diet, 3% a nutrient-restrictive diet, and 2% a dietary pattern for health reasons, researchers said.

Those on calorie-restrictive diets scored higher on depression symptoms than those following no diet, results show.

Overweight people following either a low-calorie or nutrient-restrictive diet scored even higher still, researchers found.

And any sort of diet at all affected men’s moods, the study says.

These findings directly contradict previous studies which found that low-calorie diets eased depression, researchers said.

“This discrepancy may arise because prior studies were primarily randomized controlled trials where participants adhered to carefully designed diets ensuring balanced nutrient intake,” the researchers added.

In real life, calorie-restricted diets often result in nutritional deficiencies and stress that can worsen symptoms of depression, the team noted.

For example, glucose and fatty acids are critical for brain health.

“Diets low in carbohydrates (glucose) or fats (omega-3s) may theoretically worsen brain function and exacerbate cognitive-affective symptoms, especially in men with greater nutritional needs,” the team wrote.

People on such diets also might become depressed if they fail to lose weight or if they weight-cycle, dropping pounds only to put them back on again, researchers said.

Dr. Sumantra Ray, chief scientist and executive director of the NNEdPro Global Institute for Food, Nutrition and Health in the U.K., reviewed the findings. 

He said the new study “adds to the emerging evidence linking dietary patterns and mental health, raising important questions about whether restrictive diets which are low in nutrients considered beneficial for cognitive health, such as omega-3 fatty acids and vitamin B12, may precipitate depressive symptoms.”

However, Ray added that the observed effects on depression were relatively small.

“Further well-designed studies that accurately capture dietary intake and minimize the impact of chance and confounding are needed to continue this important line of inquiry,” he said in a news release.

More information

The Academy of Nutrition and Dietetics has more on the health effects of low-calorie diets.

SOURCES: BMJ, news release, June 3, 2025; BMJ Nutrition Prevention & Health, June 3, 2025