A new trial investigates whether the MIND diet can be scaled up to manage obesity

Researchers in Sweden are testing whether a brain-healthy MIND diet can realistically be adopted by obese adults, setting the stage for future trials linking diet, gut health and mental well-being.

Study: Exploring the interaction between diet, obesity, mental health and the gut microbiota: the MIND-GUT intervention study, study protocol. Image credit: Tijana Moraca / Shutterstock

In a recent study protocol published in the journal Frontiers in Nutritionresearchers described an ongoing investigation into whether a Mediterranean DASH intervention for neurodegenerative retardation (MIND) diet is practical, acceptable and feasible for adults with obesity.

The results of this study will provide feasibility data and preliminary evidence to inform future trials examining the relationships between diet, gut microbiome, mental health and obesity, thereby guiding strategies to promote physical and psychological well-being.

Associations of obesity, mental health and nutrition

Mental health disorders and obesity often co-occur and contribute substantially to both personal suffering and public health costs. The pathways linking these conditions remain unclear, but growing evidence suggests that diet plays an important role in both weight management and emotional well-being.

In Sweden, the prevalence of overweight and obesity has steadily increased over the past two decades, particularly among young adults. More than half of Swedish adults are now above a healthy weight, with stark differences between gender, country of birth and educational level. These trends highlight the need for preventive strategies that address both physical and mental health.

Diet-induced weight loss has been associated with improved mood in obese individuals, but psychological benefits may also occur through diet-microbe interactions. Dietary patterns shape the gut microbiome, which is involved in metabolic regulation and pathways related to stress and mood.

Rationale and MIND nutrition ingredients

The Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) The diet prioritizes foods rich in antioxidants, fiber, and healthy fats that support cognitive and gut health. Instead of fully combining the Mediterranean and DASH diets, the MIND diet emphasizes ingredients believed to benefit brain and metabolic health. If proven to be practical and acceptable, this pattern may support weight loss and mental well-being in Sweden.

Trial design and participant eligibility

THE MIND-GUTS The study is a randomized clinical trial with two arms: a MIND diet intervention group and a control group receiving standard healthy eating advice. A total of 126 adults aged 25 to 50 years with obesity will be recruited from primary care clinics and the community in the Västra Götaland region of Sweden. The sample size allows for reliable estimates of feasibility while accounting for expected dropout.

Participants must have a body mass index (BMI) at least 30 kg/m², internet access and willingness to complete all procedures. If intake is difficult, the BMI limit can be reduced to 27 kg/m². Exclusion criteria included conditions or treatments that could affect dietary change, gut microbiota composition, or mental health outcomes, such as weight loss medication use, diabetes, or polycystic ovary syndrome. Ethical approval was obtained and informed consent procedures emphasized privacy and autonomy.

Intervention delivery and data collection

At baseline and at 12 weeks, trained staff will collect physical measurements, including weight, height, body composition, blood pressure, and waist and hip circumferences. Participants will complete online questionnaires assessing demographics, lifestyle behaviours, psychosocial well-being, dietary attitudes, bowel symptoms and dietary intake.

Mental health outcomes are assessed using validated self-report instruments that measure anxiety, depressive symptoms and perceived stress rather than clinical diagnoses. Adherence is measured using a simplified food checklist targeting key components of the MIND diet at baseline, week 6 and week 12.

Intervention participants receive a structured MIND eating plan that emphasizes leafy greens, berries, olive oil, whole grains, legumes, nuts, poultry, and fish. Daily energy intake is limited to 2,300 kcal for men and 1,900 kcal for women. Control participants receive standard dietary advice aligned to the Swedish guidelines without MIND targeted ingredients.

Both groups are encouraged to limit alcohol and avoid soft drinks, and both receive regular reminders, newsletters and advice to support conservation. After 12 weeks, participants complete qualitative interviews exploring acceptance, barriers and suggestions for improvement.

Microbiome Sampling and Study Results

Participants provide stool samples at baseline, week 6 and week 12 to record microbiome dynamics. Specimens are stored at home and postponed if there is recent illness, fever, diarrhea or antibiotic use that could affect the results. Laboratory processing is randomized to reduce batch effects.

Primary outcomes include compliance, retention, and acceptance. Secondary outcomes include changes in gut microbiota, anxiety, depressive symptoms, perceived anxiety, weight, fat mass, waist-to-hip ratio, and BMI. The analyzes are exploratory and intended to inform future efficacy trials.

Public Health Relevance and Future Directions

This protocol assesses whether an intervention based on the MIND diet can realistically be implemented in adults with obesity, a necessary step before scaling up interventions targeting both physical and mental health.

If feasible, this approach could inform personalized nutritional strategies and public health policies that promote brain-healthy nutrition. By integrating diet quality, emotional well-being and gut microbiota, the study aims to provide foundational evidence for future large-scale trials addressing multiple dimensions of obesity-related health.