Low-calorie diet may cause depression in men

According to the new study, nearly 30,000 Americans have been analyzed, following a low-calorie diet may increase your risk of depression symptoms, especially if you are a man or are overweight.

The study published in BMJ Nutrition Prevention and Health found that people who suppressed their calorie diet scored higher on the depression screening test compared to those who did not follow any specific diet plan. Men appear particularly vulnerable, showing increased symptoms associated with depression in multiple types of restrictive diets. This finding challenges common assumptions about the mental health benefits of dieting and suggests that real-world calorie restriction can have unexpected psychological consequences that are very different from controlled lab research.

Depression Connection

The researchers analyzed data from the National Health and Nutrition Examination Survey from 2007 to 2018. Among the 28,525 participants, participants following a calorie-restricted diet showed an increase of 0.29 points in depression score using the Verified Patient Health Questionnaire-9 scale.

In specific groups, the effect is more obvious. The depression scores for overweight patients after a calorie restriction diet increased by 0.46 points, while those on nutritional diets increased by 0.61 points. From a perspective, clinical depression is usually scored on a 27-point scale of 10 or higher.

What makes these findings particularly focus is how they contradict previous studies, suggesting that a low-calorie diet can improve mood. The key difference seems to be between carefully controlled laboratory research and dieting experience in the real world.

Why are real diets different

Previous studies have shown that the emotional benefits of calorie restriction were mainly randomized controlled trials in which participants carefully designed diets with balanced nutrition. On the contrary, real-life calorie restrictions often lead to nutritional deficiencies and physiological stress.

Researchers point out that a real-world restricted diet often leads to a lack of protein, essential vitamins and minerals. These nutritional gaps can worsen depression symptoms, especially cognitive and emotional aspects of the condition.

Another factor could be the psychological impact of weight loss or failure in weight cycles – weight loss is simply to restore weight. Unlike controlled studies that usually succeed in losing weight, real-world dieters often struggle with compliance and may feel frustrated if the results do not match expectations.

Men face higher risks

The study reveals how restrictive diets affect gender differences in mental health. Men who follow any type of restrictive diet exhibit higher scores for somatic depression symptoms – physical manifestations such as fatigue, sleep problems, and appetite changes.

Men with nutritional restrictive diets also experience increased symptoms of cognitive impact, including depression, introsity and difficulty concentrating. This is an increase of 0.40 points compared to women who did not follow any special diet.

There are several factors that explain a man’s vulnerability. Men often have higher nutritional needs, making them more susceptible to defects when limiting their food intake. Furthermore, men often prefer high-fat foods and frequent fast food restaurants than women, making nutritional restrictions particularly challenging.

Brain chemical factors

Researchers believe that glucose and omega-3 fatty acids are crucial for brain health. A low-carb or fat diet may worsen brain function and exacerbate depression symptoms, especially in men with high nutritional needs.

This biological explanation and research suggests that men have different brain activation patterns in risk decision making than women. Men often show activation in multiple brain regions, which may make them more sensitive to nutritional disruptions that affect neurological function.

The study also found that defects in essential nutrients such as vitamin B12, folic acid and iron can impair energy metabolism, which worsens the physical symptoms of men experiencing more severe depression.

Weight factor

Overweight people face special challenges with restrictive diets. Both the calorie-restricted diet and the nutrient-restricted diet were associated with higher depression scores in the group, which was associated with studies showing that weight loss can improve mood.

The key difference seems to be the actual weight loss success. Controlled studies often lead to better adherence to diet and weight loss. In the real world, barriers such as support and lack of motivation often prevent successful weight loss.

When overweight people do not lose weight or experience weight cycles, they may experience worsening depression symptoms. This creates a potentially harmful cycle in which tools designed to improve health outcomes can lead to psychological distress.

Physical symptoms pattern

Overweight participants on the nurturing diet showed a particular increase in somatic depression symptoms. These physical manifestations include low energy, poor sleep quality and difficulty concentrating – symptoms that match existing studies link restrictive dieting to physical health issues.

Somatic symptoms may reflect the body’s stress response to nutrient limitation, especially when the individual is already dealing with metabolic challenges associated with overweight. Even if the mood itself is not severely affected, this physiological stress can manifest as symptoms of depression.

Beyond simple health and unhealthy

This study challenged an oversimplified narrative of “healthy eating well, unhealthy eating poorly” that dominated nutrition discussions. While previous studies have been showing that diets rich in whole foods reduce the risk of depression, this study shows that the approach to diet changes is crucial and the end result.

Most participants (of nearly 30,000 studies under study, 87% did not follow any specific diet plan. Among those who were on a diet, 8% followed a calorie-restricted approach, 3% used a nutrition-restricted approach, and only 2% followed a dietary pattern like the diabetes diet.

Interestingly, none of the established dietary patterns were associated with depression scores, suggesting that medically supervised or well-defined dietary plans may be safer than self-guided restrictive efforts.

Classification Challenge

One limitation beyond typical coverage is how people categorize their diets. The study relies on self-reported dietary patterns, and participants may not be able to accurately categorize what they actually eat.

For example, researchers found that although sugar and fiber are both carbohydrates, people who report “low sugar” and “low fiber” diets cannot be used as agents for “low carbohydrate” diets. This suggests that many dieters do not fully understand the nutritional content of their chosen diet.

The “Diabetes Diet” option did not provide descriptions for participants, but many chose this category. Without knowing what constitutes a diabetic diet, people may have been following a very different diet while thinking they are on the same plan.

This confusion of classification may partly explain why certain dietary methods do not have obvious mental health effects—categories may be too broad or inaccurate to capture meaningful patterns.

The gap between laboratory and reality

The study highlights the key disconnect between controlled research environments and real-life dieting experiences. Laboratory studies often provide participants with carefully planned meals, nutrition education, and ongoing support, a condition that independent dieters rarely exist.

In a controlled environment, participants usually achieve weight loss goals and maintain balanced nutrition throughout the study period. These ideal conditions may explain why lab studies have always shown the mental health benefits of calorie-limited.

Real-world dieters face many challenges lacking in the research environment: unclear nutrition guidance, limited food preparation skills, financial constraints, social stress, and a lack of professional supervision. These factors can translate potentially beneficial dietary changes into sources of stress and nutritional inadequacy.

Support system differences

Another key factor involves social and professional support systems. Study participants usually undergo regular examinations, educational materials, and professional guidance throughout the dietary intervention. Most independent dieters are not able to obtain a registered dietitian, psychologist or other professional who can help with the mental health challenges of restrictive diets.

This support gap may be particularly important for men, whose research shows that there is less chance of seeking help for nutrition and mental health issues. Without proper guidance, men who attempted a restrictive diet may be particularly susceptible to the depressive symptoms recorded in this study.

Clinical significance

These findings have a direct impact on healthcare providers who recommend dietary changes. The study shows that telling patients only “reduce” or “cut carbohydrates” without taking into account individual risk factors may inadvertently worsen mental health outcomes.

Healthcare professionals may need to screen for risk factors for depression before recommending a restrictive diet, especially for male and overweight patients. The study shows that tailor-made dietary consultations based on gender and BMI can help prevent diet-induced depression.

Professor Sumantra Ray commented on the study that the study “adds emerging evidence linking to dietary patterns and mental health, suggesting restrictive diets that are less restrictive diets that are beneficial to cognitive health, such as Omega-3 fatty acids and vitamin B12, may reduce depression symptoms.”

Main research results

A comprehensive analysis reveals several key insights:

• Total depression scores on the restricted calorie diet increased by 0.29 points
• Overweight individuals showed an increase of 0.46-0.61 points, depending on diet type
• Men have higher symptoms of depression in all three restrictive diet categories
• Nutrition-restricted diets particularly affect cognitive affective symptoms in men
• Self-reported dietary classification shows inaccuracies of participants
• Dieting results in real world are very different from controlled laboratory studies
• Weight cycling and weight loss failures can lead to dietary depression

expect

The study opens up new questions about how to balance physical health goals with mental health protection. Although calorie restriction remains an important tool for managing obesity and related health conditions, the findings suggest that implementation methods require careful consideration.

Future research should examine whether providing better nutrition education, mental health support or progressive modifications can preserve the physical benefits of calorie restriction while minimizing the risk of depression. Researchers specifically call for intervention studies to test dietary recommendations tailored based on individual risk factors.

The study also highlights the need for more studies that simulate realistic dieting conditions rather than ideal laboratory environments. Understanding how dietary changes affect mental health in real-life situations, including obstacles, setbacks, and imperfect compliance, may lead to more effective and safer weight management strategies.

As obesity rates continue to rise worldwide, finding ways to help people lose weight without causing depression has become increasingly important. This study shows that the path forward may require more personalized, well-supervised approaches rather than a certain level of dietary advice.