Insights
Low-calorie diets may increase risk of depressive symptoms, study finds

Following a low-calorie diet is linked to a heightened risk of depressive symptoms, particularly among men and individuals who are overweight, according to new research.
The study, which analysed data from 28,525 adults, found that people on calorie-restrictive diets scored higher on measures of depressive symptoms than those not following any specific dietary plan.
Men and those classified as overweight appeared especially vulnerable to the mental health effects of restrictive eating, the analysis showed.
Professor Sumantra Ray is chief scientist and executive director of the NNEdPro Global Institute for Food, Nutrition and Health.
Ray said: “This 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.
“But the effect sizes are small, with further statistical limitations limiting the generalisability of the findings.
“Further well designed studies that accurately capture dietary intake and minimise the impact of chance and confounding are needed to continue this important line of inquiry.”
Researchers used data from 28,525 adults who took part in the US National Health and Nutrition Examination Survey (NHANES) between 2007 and 2018.
All participants completed the Patient Health Questionnaire-9 (PHQ-9), a widely used tool that assesses depressive symptoms based on nine questions relating to mood, sleep and daily functioning.
Just under 8 per cent of participants reported experiencing depressive symptoms.
Of the full sample, 29 per cent had a healthy weight (7,995 participants), 33 per cent were overweight (9,470 participants), and 38 per cent were classified as obese (11,060 participants).
Participants were divided into four dietary categories: those following calorie-restrictive diets, those on nutrient-restrictive diets (limiting intake of fat/cholesterol, sugar, salt, fibre, or carbohydrates), those adhering to established dietary patterns (such as diabetic diets), and those not following any specific diet.
Most respondents (87 per cent) reported not following any particular dietary approach.
Specifically, 25,009 participants were not on any specific diet, 2,026 (8 per cent) followed calorie-restrictive diets, 859 (3 per cent) followed nutrient-restrictive diets, and 631 (2 per cent) adhered to established dietary patterns.
People on calorie-restrictive diets scored 0.29 points higher on the PHQ-9 depression scale than those not on any diet.
Among overweight individuals following a calorie-restrictive diet, the increase was 0.46 points. Those following nutrient-restrictive diets saw a 0.61-point increase.
The study also examined specific types of depressive symptoms.
Calorie-restrictive diets were associated with higher cognitive-affective symptom scores, which measure the relationship between thoughts and feelings.
Nutrient-restrictive diets were linked to higher somatic symptom scores, indicating excessive distress and anxiety about physical symptoms.
These scores also varied by sex: a nutrient-restrictive diet was associated with higher cognitive-affective symptom scores in men than in women not on a diet, while all three types of diet were associated with higher somatic symptom scores in men.
Additionally, people living with obesity who followed established dietary patterns had higher cognitive-affective and …
The findings contrast with earlier studies that suggested low-calorie diets might help reduce depressive symptoms.
The authors explained that many prior studies were conducted under controlled conditions with carefully designed, nutritionally balanced diets.
They wrote: “In contrast, real-life calorie-restricted diets and obesity often result in nutritional deficiencies (particularly in protein, essential vitamins/minerals) and induce physiological stress, which can exacerbate depressive symptomatology including cognitive-affective symptoms.”
They also suggested that unsuccessful weight loss attempts or cycles of weight loss and regain (known as weight cycling) may contribute to poorer mental health outcomes.
To account for the gender differences, the researchers highlighted the role of nutrients like glucose and omega-3 fatty acids in supporting brain function.
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,” they noted.
The authors noted that, as an observational study, their research could not establish causation.
They also acknowledged the possibility that some participants may have inaccurately reported their dietary habits.
Wellness
Researchers use prehistoric skeletons to study ageing

An archaeologist from the University of York is leading a new study into how societies viewed ageing, wisdom and experience over thousands of years.
Dr Lindsey Büster’s research claims to be the first to focus on the lives and experiences of older adults in prehistoric and Roman Europe, examining skeletons and objects from collections including York Museums Trust.
The project, called Age-Old Stories, aims to challenge existing stereotypes and ageism by exploring how earlier societies viewed age, wisdom and experience.
“They have a very large collection of Roman human remains from across Yorkshire and that’s going to be a really important assemblage for us,” said Dr Büster.
The ultimate aim is for the research to provide strong examples of why making older adults more visible in policy-making and public life is so important,” said Dr Büster.
“Ageing is not a marginal experience, it is a central part of human history and we should have better strategies for valuing and celebrating it today.”
Archaeological discoveries already suggest that older adults were central figures in many past societies.
In Scarborough, the remains of Gristhorpe Man – Britain’s best-preserved Early Bronze Age skeleton – were analysed and suggested he was aged between 45 and 60 years, tall and muscular, and nourished by a rich diet.
“He is over 45 and he was buried in this log coffin, which would’ve been hugely time consuming, hugely labour intensive and he’s buried with a dagger,” said Dr Büster.
“These are all the trappings of a high-status individual.”
The project will work in partnership with York Museums Trust to create a new exhibition and public events, and will also collaborate with Age Friendly York.
News
Weight loss jabs should be first-line obesity treatment in most cases, new guidance states

Weight loss jabs Mounjaro and Wegovy are so effective they should be the first treatment for obesity “in almost all cases”, according to new medical guidance.
The European Association for the Study of Obesity praised the drugs’ effectiveness and wider health benefits in new guidance to doctors.
It described them as slimming aids that can also cut the risk of related conditions such as high blood pressure and type 2 diabetes.
Three in ten Britons – around 16m adults – are obese, but only 1.5m use the injections, most bought privately at about £200 a month.
Trials have shown adults using semaglutide, the active ingredient in Wegovy and Ozempic, lost about 14 per cent of their body weight over 72 weeks.
Those taking tirzepatide – marketed as Mounjaro and sometimes dubbed the “king kong” of weight loss jabs – lost about 20 per cent over the same period.
Dr Andreea Ciudin, co-first author of the guidance from the Autonomous University of Barcelona, said the drugs were “completely transforming care of obesity and its complications”.
She added: “Even though there are several options on the market, the reality is that semaglutide and tirzepatide are so effective that they should be the first choice in almost all cases.”
The guidelines were produced by an international team of experts, including contributors from the UK.
They analysed existing studies and created an algorithm to help doctors decide the best treatment based on a patient’s weight and associated conditions.
They concluded that tirzepatide and semaglutide should be considered the “medications of choice” when a substantial level of total body weight loss is required.
When a lesser degree of weight loss is the aim, other medicines such as liraglutide, naltrexone–bupropion and phentermine–topiramate may be appropriate.
The guidance comes after health secretary Wes Streeting pledged this week to make injections available to millions more patients on the NHS.
Speaking at the Labour Party conference in Liverpool, he said it was unfair that wealthier people had been able to benefit from the drugs’ “transformative” effects “on their health, their confidence and their quality of life” while those unable to pay privately had gone without.
He added: “Weight-loss jabs could help us finally defeat obesity.
“Our mission is to ensure that the best science, the best healthcare and the best innovations are available not just to some, but to all.”
Research
Brain shape changes could offer early warning signs of dementia, study suggests

Ageing alters the brain’s shape in measurable ways that could provide early warning signs of dementia, potentially years before symptoms appear, researchers say.
Analysis of more than 2,600 brain scans from adults aged 30 to 97 revealed significant alterations in brain geometry linked to declines in memory, reasoning and other cognitive functions.
The inferior and anterior parts of the brain expanded outward, while the superior and posterior regions contracted inward. These uneven shifts were most evident in older adults showing cognitive decline.
Researchers at the University of California, Irvine’s Centre for the Neurobiology of Learning and Memory found that people with more pronounced posterior compression performed worse in reasoning tests, suggesting these geometric markers directly relate to brain function.
“Most studies of brain ageing focus on how much tissue is lost in different regions,” said Niels Janssen, senior author and professor at Universidad de La Laguna in Spain and visiting faculty at the CNLM.
“What we found is that the overall shape of the brain shifts in systematic ways, and those shifts are closely tied to whether someone shows cognitive impairment.”
One important implication involves the entorhinal cortex – a small but vital memory hub in the medial temporal lobe.
The study suggests age-related reshaping may press this region against the hard base of the skull.
The entorhinal cortex is one of the first areas where tau, a toxic protein linked to Alzheimer’s disease, accumulates.
The findings raise the possibility that mechanical and gravitational forces may contribute to its vulnerability in Alzheimer’s – a potential disease mechanism not previously considered.
“This could help explain why the entorhinal cortex is ground zero of Alzheimer’s pathology,” said study co-author Michael Yassa, director of the CNLM and James L McGaugh endowed chair.
“If the ageing brain is gradually shifting in a way that squeezes this fragile region against a rigid boundary, it may create the perfect storm for damage to take root. U
“nderstanding that process gives us a whole new way to think about the mechanisms of Alzheimer’s disease and the possibility of early detection.”
The researchers say their geometric approach could eventually provide new markers for identifying dementia risk, potentially before symptoms emerge.
“This isn’t just about measuring brain shrinkage,” added Janssen.
“It’s about seeing how the brain’s architecture responds to ageing and how that architecture predicts who is more likely to struggle with memory and thinking.”
The patterns were replicated in two independent datasets, reinforcing the consistency of these shape changes as a hallmark of ageing.
“We’re just beginning to unlock how brain geometry shapes disease,” said Yassa.
“But this research shows that the answers may be hiding in plain sight – in the shape of the brain itself.”
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