Calorie Restricted Diets Are Associated with Depression

By Wayne Persky

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A study analyzing data from nearly 30,000 Americans shows how restrictive dieting can increase depressive symptoms, with particularly pronounced effects in men and individuals with higher body mass index (BMI) (Menniti, Meshkat, Lin, Lou, Reichelt, and Bhat, 2025).1 Published in BMJ Nutrition, Prevention & Health, this research challenges common assumptions about the universal benefits of calorie restriction, and suggests a need for more personalized approaches to dietary interventions.

Researchers analyzed data from 28,525 adults

who participated in the US National Health and Nutrition Examination Survey (NHANES) between 2007 and 2018. Participants completed comprehensive dietary assessments alongside the Patient Health Questionnaire-9 (PHQ-9), a validated tool for measuring depression severity. This cross-sectional approach provided researchers with substantial data to examine the relationships between restrictive dietary patterns and mental health outcomes across various populations.

The study specifically focused on two main types of dietary restriction: calorie-restrictive diets (limiting overall energy intake) and nutrient-restrictive diets (eliminating specific food groups or nutrients). These patterns were compared against individuals following no specific dietary restrictions to identify potential mental health consequences of common dieting approaches.

The study confirmed a connection.

The results showed a clear association between restrictive dieting and increased depressive symptoms. Overall, individuals following calorie-restrictive diets showed a 0.29 point increase in PHQ-9 depression scores compared to those not following any specific diet. While this might seem modest, it represents a measurable shift toward more significant depressive symptoms across large populations.
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The study identified 2,508 participants (7.79% of the total sample) who self-reported symptoms of depression, providing a substantial cohort for analyzing the relationship between dietary patterns and mental health outcomes. This prevalence aligns with national depression statistics, suggesting that the findings of the study are representative of the broader American population.

There were gender-specific differences.

Men demonstrated particularly pronounced susceptibility to diet-related mental health effects. Male participants following restrictive diets showed higher somatic symptom scores (physical manifestations of depression such as fatigue, sleep disturbances, and appetite changes) compared to men not following specific diets. Additionally, men on nutrient-restrictive diets experienced a 0.40 point increase in cognitive related symptom scores, including mood changes, concentration difficulties, and negative thought patterns.

This gender disparity may reflect several factors. Men typically have higher baseline caloric and nutritional requirements due to greater muscle mass and metabolic demands. When these needs aren't met through restrictive dieting, the physiological stress may manifest more readily as depressive symptoms. Additionally, men may be less likely to recognize or address the emotional impacts of dietary changes, allowing symptoms to accumulate before being acknowledged.

The finding that men experience more somatic symptoms aligns with broader research showing that depression in men often presents differently than in women, with physical symptoms sometimes predominating over emotional ones. This pattern suggests that healthcare providers should be particularly vigilant for depression symptoms in male patients undertaking restrictive diets.

Patient weight affected diet-related depression risk.

Individuals with elevated BMI showed increased vulnerability to diet-related depressive symptoms. Overweight participants following calorie-restrictive diets experienced a 0.46 point increase in PHQ-9 scores, while those on nutrient-restrictive diets showed an even more substantial 0.61 point increase. These findings are particularly concerning given that overweight individuals are often specifically encouraged to pursue restrictive dieting for health benefits.

This relationship may reflect the complex interplay between weight stigma, diet culture pressures, and the psychological stress of restriction. Individuals with higher BMI often face societal pressure to diet and may experience shame or guilt around food choices, potentially amplifying the mental health impacts of dietary restriction. Additionally, the metabolic changes associated with calorie restriction, including alterations in hormones like leptin and ghrelin, may have more pronounced effects on mood regulation in individuals with higher baseline weight.

This creates a paradox,

since those most likely to be prescribed restrictive diets for health benefits may be the most vulnerable to the associated mental health consequences. This finding underscores the need for careful monitoring and potentially alternative approaches for weight management in higher BMI populations. And it certainly helps to explain why the GLP-1 medications are so popular, despite their numerous side effect risks.

Understanding the mechanisms that are involved.

The relationship between dietary restriction and depression likely involves multiple interconnected pathways. Calorie restriction can lead to significant physiological changes, including alterations in neurotransmitter production, hormone regulation, and blood sugar stability, and all of these factors directly influence mood and cognitive function.

Nutritional deficiencies common in restrictive diets may particularly impact brain function. Essential nutrients including omega-3 fatty acids, B vitamins, vitamin D, and minerals like zinc and magnesium play crucial roles in neurotransmitter synthesis and neural protection. When restrictive diets eliminate entire food groups or severely limit caloric intake, these critical nutrients may become insufficient to support optimal brain function.

The psychological stress of restriction itself compounds these physiological effects. Food restriction can increase cortisol production, trigger anxiety around food choices, and create cognitive burden from constant dietary monitoring. These psychological stressors may be particularly burdensome for individuals already managing weight-related stigma or pressure to achieve unrealistic body standards.

What are the implications?

Although the research findings didn't consider this, a degree in psychiatry is certainly not needed for anyone to recognize that the association with depression enhancing factors such as adverse neurotransmitter production, hormone regulation, and blood sugar stability, is almost surely the main reason why most patients who attempt-restricted diets are unable to maintain them in the long run. Apparently, those few who are able to successfully follow a restricted diet for the long term are unusually dedicated individuals who are able to “soldier through” despite oppressive symptoms that finally overwhelm most people.

Reviews of randomized controlled trials show that only 20–35% of dieters maintain strict adherence for 1 year, and roughly 10–20% sustain meaningful calorie restriction and weight loss for 2–5 years.​

The fact that such a small percentage of dieters are able to stick with a restricted diet for the long term, suggests that virtually everyone experiences these symptoms to at least some extent. That doesn't bode well for the future of dieting to accomplish the goal of weight loss. Yet physicians continue to recommend dieting and patients continue to attempt to follow that advice.

Clinical implications:

Obviously most healthcare providers may need to reconsider their procedures for prescribing or recommending restrictive diets. The research suggests that dietary interventions should be tailored, based on patient sex, and BMI status, with special monitoring for depressive symptoms in high-risk groups, such as men and individuals with elevated BMI.

Rather than severe calorie restriction, gradual reductions in caloric intake while maintaining nutritional adequacy may minimize mental health risks. Emphasizing food quality over quantity, incorporating regular physical activity, and addressing psychological relationships with food may provide more sustainable and mentally healthy approaches to dietary change.

The bottom line:

Hundreds of diets have been promoted over the decades, but they've all been vulnerable to the limiting factors highlighted by this study. While nutrient-restricted diets will continue to be effective for treating autoimmune diseases such as IBD, calorie-restricted diets will continue to be doomed to fail, unless some sort of honest-to-goodness research breakthrough occurs.

Reference:

1. Menniti, G., Meshkat, S., Lin, Q., Lou, W., Reichelt, A., and Bhat, V. (2025). Mental health consequences of dietary restriction: increased depressive symptoms in biological men and populations with elevated BMI. BMJ Nutrition, Prevention & Health, (8). Retrieved from https://nutrition.bmj.com/content/8/1/10