A new observational study, published in the BMJ Nutrition, Prevention & Health on 2 June, has cast fresh light on the potential psychological costs of calorie-restricted dieting.

The research, which analysed data from tens of thousands of participants, found that those who engage in calorie or nutrient restriction are more likely to experience symptoms associated with depression. The results were particularly striking among individuals classified as overweight, where the risk of depressive symptoms was even more pronounced.

Dieting, often hailed as the path to better health and weight control, remains a deeply popular practice. Yet, this very act of restricting what we eat may be doing subtle harm to our minds. According to the study’s findings, participants who were actively limiting their caloric intake reported higher average scores on the PHQ-9, a widely used screening tool that measures depression severity.

Even a seemingly small increase in score—0.29 points higher for dieters overall—can signal a meaningful shift in mood at the population level. Among those with overweight, the increase was more notable: 0.46 points higher for calorie restriction and an even more substantial 0.61 for nutrient restriction.

This isn’t the first research to examine the link between dieting and mental health, but consensus has proved elusive. Many earlier studies have produced mixed or inconclusive results, leaving both clinicians and the public with questions about what truly happens when we decide to go on a diet.

The new study, while not able to prove causation due to its observational design, nonetheless injects fresh urgency into the conversation.

One key takeaway from the research is the psychological burden that often accompanies restrictive eating. Experts in psychiatry and nutrition emphasise that people tend to divide foods into binary categories—labeling them as either “good” or “bad.” Over time, this mindset can warp self-image. Weight becomes a proxy for self-worth. The figure on the scale isn’t just a number; it starts to feel like a judgement.

Professionals dealing with eating disorders and body image issues notice similar patterns. Many clients embark on restrictive diets with hopes of control—usually with weight loss as the aim. But physiological reality tends to intervene.

Calorie restriction can sap mental resilience and amplify stress. It’s common for dieters to end up eating more than planned, followed by feelings of guilt or failure. The loop is exhausting—mentally and emotionally.

The physiological impact of extended restrictive diets is also significant. Deficiencies in protein, iron or vitamin D can arise over time when food groups or essential nutrients are limited. The attempts to “fix” one aspect of health may end up disrupting others, particularly mental well-being.

Dieters may find themselves becoming upset by things that wouldn’t normally bother them or losing interest in activities that once brought joy. The restriction itself becomes a trap—consuming mental energy while failing to provide lasting solutions.

So what exactly is a calorie? In simple terms, it’s a unit of energy—a measure of how much fuel a food contains and how much energy our bodies expend during activity. Daily calorie needs vary based on factors such as age, sex and activity level. On average, most women require at least 1,600 calories per day to maintain weight, while men generally need at least 2,000.

Yet, despite these needs, many people attempt diets that sharply cut calorie intake. Such approaches rarely yield sustainable success. Often, clients seek professional help after repeated failed attempts at calorie restriction.

What works better? The evidence points strongly toward balanced eating patterns—approaches that are both nourishing and sustainable over time. Mindful eating techniques can be particularly valuable here. By tuning into genuine hunger signals and learning to recognise fullness cues (which are easily missed in our distracted lives), people are better able to regulate intake naturally.

A simple strategy: pause towards the end of a meal and allow time for fullness signals to register. This can help prevent overeating without feeling deprived. Likewise, sticking to regular meal times helps curb random snacking and prevents excessive hunger between meals—a common trigger for overeating.

Another helpful tip: avoid thinking about foods in moral terms. Labelling foods as “good” or “bad” often backfires, leading to guilt and anxiety rather than healthier choices. Instead, focus on foods that provide nourishment and support satiety—a positive approach that encourages balance rather than restriction.

For those struggling to break out of restrictive eating patterns or negative self-judgement around food, seeking support from a registered dietitian or qualified nutritionist is advisable. These professionals can provide personalised advice and accountability tailored to individual needs and lifestyles.

The study also highlights certain foods that can support mood and mental well-being. Fatty fish such as salmon and sardines are rich sources of omega-3 fatty acids—nutrients shown in research to reduce symptoms of depression and promote cognitive function. Including such foods as part of a varied diet can play a role in supporting both physical and psychological health.

It’s important to remember that dieting is not only about numbers on a scale but about overall well-being. Restrictive approaches may promise quick results but often come at the expense of happiness—and are seldom sustainable in the long term.

Many people start dieting with good intentions: better health, improved appearance or greater self-esteem. Yet, when these efforts turn into cycles of deprivation followed by loss of control and guilt, the result is rarely positive. Persistent restriction drains mental energy and can contribute to feelings of sadness or irritability.

The science suggests a different way forward: one grounded in balance, variety and self-compassion. Eating regular meals filled with whole grains, lean proteins, vegetables and healthy fats provides satiety and nourishment without triggering cycles of restriction and rebound. Practising mindful eating encourages us to reconnect with our bodies’ natural signals rather than overriding them in pursuit of arbitrary targets.

Successful weight management is not about rigid rules but about finding an approach that supports both physical health and emotional resilience. This means respecting individual needs, accepting occasional indulgences without guilt and seeking support when challenges arise.

The conversation about dieting and depression is far from over but the latest research adds an important dimension: it’s not just what we eat but how we think about food—and ourselves—that matters most. For those striving for long-term health and happiness, balance remains the surest path.