When Cutting Calories Cuts Into Your Mood: The Mental Health Cost of Dieting

In the pursuit of fitness and weight loss, many people adopt low-calorie diets, believing that eating less will lead to a healthier body. However, cutting calories excessively can have unintended consequences—not just for physical health, but for mental well-being. Emerging research suggests that restrictive dieting might be linked to mood disorders, including depression.

Anyone who has ever traded a bag of chips for a bowl of salad understands the challenge. Dieting isn't always a pleasant experience. Now, research suggests that the emotional lows that often accompany it may not just be temporary.

A recent study published in BMJ Nutrition, Prevention & Health indicates that reducing calorie intake could negatively impact mental well-being. In fact, it has been associated with an increased risk of depression, especially among men and individuals who are overweight.

What’s driving this decline in mood? And why does limiting food intake have such a powerful effect on mental well-being? Let’s break it down.

The Impact of Eating Less on Mental Health

Researchers from the University of Toronto examined health data from 28,525 U.S. adults over a decade, analyzing their eating habits, dieting behaviors, and clinical evaluations for depression. The findings shed light on the potential risks associated with calorie restriction.

Individuals adhering to low-calorie diets were observed to have elevated depressive symptom scores, including fatigue, difficulty concentrating, and a diminished sense of enjoyment in daily activities.

The researchers suggest that this may stem from calorie restriction causing “nutritional deficiencies,” particularly in essential proteins and vitamins that play a vital role in brain function and mood stability.

The researchers noted that “inconsistent weight loss or frequent fluctuations while dieting in real-life scenarios could contribute to worsening depressive symptoms.”

They further emphasized that the brain relies on a continuous supply of glucose for energy, along with sufficient omega-3 fatty acids to maintain optimal function. A deficiency in these nutrients, they warned, may negatively impact brain health.

Why Men and Obese Individuals May Be More Vulnerable

The study uncovered an intriguing trend: men appear to experience the psychological effects of dieting more intensely than women.

Although both genders reported mood declines, men—regardless of whether they were following a calorie-restricted diet or another type—tended to exhibit worse mental health outcomes than women. Among the 28,525 participants, 14,329 were women and 14,196 were men.

One possible reason is that men have higher nutritional requirements than women, making food restriction more impactful. Additionally, some researchers suggest that men may simply find dieting more challenging to maintain.

The study also revealed that low-calorie diets were more prevalent among individuals who were overweight or obese, and this group exhibited higher rates of depressive symptoms compared to those who were not dieting.

But haven’t some studies suggested that certain low-calorie diets can actually improve mood and alleviate depression? Why does this research indicate otherwise?

According to researchers, the key difference lies in the context.
Previous studies were conducted in highly controlled environments, where participants adhered to well-balanced, supervised diets. In contrast, real-world dieting often lacks structure, tends to be more restrictive, and frequently falls short in essential nutrients—factors that can contribute to a decline in mental health rather than an improvement.

The Link Between Calories and Mental Health

Food is more than just fuel—it directly impacts brain function, neurotransmitters, and hormonal balance. A well-rounded diet provides essential nutrients like omega-3 fatty acids, vitamins, and minerals that help regulate mood. When calorie intake drops dramatically, the brain struggles to produce enough serotonin and dopamine, two key neurotransmitters responsible for happiness and emotional stability.

Nutrient Deficiency and Mood Swings

A low-calorie diet often lacks sufficient carbohydrates and fats, both of which are crucial for cognitive function. Carbohydrates, in particular, help produce serotonin, a neurotransmitter that influences mood and sleep. Cutting them out completely or reducing intake drastically can lead to irritability, anxiety, and even symptoms of depression.

Fats, especially healthy fats from sources like nuts, avocados, and fish, are vital for brain function. Without them, the body's ability to regulate emotions weakens, making it harder to cope with stress.

Prioritizing Healthy Eating

The key message? It's not solely about reducing food intake—it's about choosing the right foods.
Experts stress that proper nutrition is fundamental to both physical and mental well-being.

"Extensive research has consistently examined the effects of ‘healthy’ versus ‘unhealthy’ diets," the researchers explained. "Findings indicate that diets rich in minimally processed foods, fresh fruits and vegetables, whole grains, nuts, seeds, lean proteins, and fish are associated with a lower risk of depression."

"In contrast, diets high in ultra-processed foods, refined carbohydrates, saturated fats, processed meats, and sweets have been linked to a greater risk of depressive symptoms," the researchers explained.

However, they cautioned that the issue is not as straightforward as simply choosing one type of diet over another. "To lower the risk of depressive symptoms, individuals should aim for a well-balanced, nutritious eating pattern. The idea of a strict divide between ‘healthy’ and ‘unhealthy’ diets oversimplifies the complexity of real-world eating behaviors," they added.

Final Thoughts

While calorie control can be helpful for weight management, going too far can harm mental health. Depression, anxiety, and irritability may all stem from nutritional deficiencies and the stress of restrictive eating. A happy mind needs nourishment—both physically and emotionally—so striking a balance is key.

If you've ever felt down while dieting, it might be worth reevaluating your approach. After all, feeling well is just as important as achieving fitness goals.

References:

1. Speakman, John R., and Sharon E. Mitchell. "Caloric restriction." Molecular Aspects of Medicine 32, no. 3 (2011): 159–221.
   https://www.sciencedirect.com/science/article/abs/pii/S009829971100032X

2. Naidoo, Uma. This is Your Brain on Food: An Indispensable Guide to the Surprising Foods That Fight Depression, Anxiety, PTSD, OCD, ADHD, and More. Hachette UK, 2020.
   https://books.google.co.in/books?hl=en&lr=&id=G3TBDwAAQBAJ

3. Thayer, Robert E. Calm Energy: How People Regulate Mood with Food and Exercise. Oxford University Press, 2003.
   https://books.google.co.in/books?hl=en&lr=&id=yl-3aHKzdckC

4. BMJ Nutrition, Prevention & Health, 2024.
   https://bmjgroup.com/low-calorie-diets-linked-to-heightened-risk-of-depressive-symptoms/

(Rehash/Mradula U Naik/MSM)