Open research questions in Obesity, Physical Activity, Diet

What the literature leaves open

• Future research should focus on validating these findings in larger, multicenter cohorts, establishing standardized age and sex specific NC reference values, and evaluating the integration of NC measurement into routine school health programs to determine its impact on early identification and management of childhood overweight.

  Neck circumference as an anthropometric marker of overweight among school-aged children in Bharatpur, Nepal: A community-based study · 2026 · DOI

• A similar small weight gain was dismissed in another study (14), despite a significant associated increase in obesity rate, but such a dismiss- al of obesity rate increases accompanied by only small absolute weight gains in a population might inap- propriately discount a clinically highlighted weight difference limited to a subpopulation.

  Infections in Infancy and Association with Long-Term Weight Gain and Obesity in Children, Southern California, USA · 2026 · DOI

• Abdulrahman I. Alaqil * College of Education, Department of Physical Education, King Faisal University, Al-Ahsa, Saudi Arabia Background: Compounded by physical inactivity and an obesogenic environment, adolescent obesity represents a significant public health challenge for Saudi Arabia. Drawing on Social Cognitive Theory (SCT) as a conceptual lens, this study aimed to compare obesity-related risk behaviors among physically active and physically inactive male Saudi adolescents. Method: Using a cross-sectional design and convenience sampling, male Saudi high school students (N = 124) aged 16–17 years in Riyadh were classified into physically active (n = 70; self-reported vigorous-intensity activity or structured ≥3 days/week) and physically inactive (n = 54) participants. BMI was classified according to International Obesity Task Force (IOTF) cutoffs, and waist-toheight ratio (WHtR) defined abdominal obesity. Lifestyle behaviors (PA, screen time, sleep, and diet) were assessed using the Arab Teen Lifestyle Study (ATLS) questionnaire. Results: Physically inactive participants had a significantly higher BMI than physically active peers (30.28 vs. 23.64 kg/m2; p < 0.001; d = 1.060), waist circumference (97.35 vs. 85.46 cm; p < 0.001; d = 0.866), and WHtR (0.562 vs. 0.488; p < 0.001; d = 0.927). By IOTF criteria, 51.9% of physically inactive participants were obese versus 17.1% of physically active participants, and 72.2% exhibited abdominal obesity (WHtR ≥ 0.50) versus 31.4%. Physically active participants accumulated significantly greater METs-min/week (4,083.9 vs. 2,225.0; p < 0.001; d = 0.667) and PA minutes/week (795.6 vs. 421.9; p < 0.001; d = 0.758); 68.6% were highly active versus 24.1% of physically inactive participants, while 63.0% of physically inactive participants were sedentary. Screen time and sleep did not differ significantly between groups; insufficient sleep was prevalent in both groups (84.3% vs. 83.3%). Of ten dietary behaviors assessed, only fresh fruit consumption was significantly higher among physically active participants (5.44 vs. 4.24 days/week; p = 0.006; d = 0.520). Conclusion: Physically active was associated with lower obesity risk in male Saudi adolescents, with large between-group differences in BMI, WHtR, and abdominal obesity. Unsatisfactory screen time and sleep profiles across both groups suggest a pervasive obesogenic environment irrespective of PA status. These crosssectional findings highlight the potential value of PA promotion, dietary reforms, and screen time and sleep initiatives for this population.

  Physical activity participation and obesity-related risk behaviors among male Saudi adolescents: a social cognitive theory perspective · 2026 · DOI

• The limitations of this study include the food consumption data collection method using a 24- hour food recall does nit necessarily reflect long term dietary patterns that influence nutritional status.

  The Relationship Between Food Consumption and Nutritional Status in School-Age Children · 2026 · DOI

• The inter- pretation of the scores across the included initiatives should, however, be interpreted with caution as this tool awards more points for clear reporting of elements that were not necessarily relevant to all of the initiatives and presenting the PA prevalence by specific categories, ra- ther than the actual quality of the initiatives; further re- finement is warranted.

  Cardiorespiratory fitness and body mass index of Nigerian youth: A FitnessGram-based assessment · 2026 · DOI

• Contrary to this prior 355 research, we found limited evidence that low accessibility influenced adolescent F&V DFC 356 – it emerged as a barrier only in the free listing and pile sorting exercises, without mention in 357 the FGDs.

  Healthy diet perceptions and drivers of fruit and vegetable food choices among adolescents in Benin: a qualitative study · 2026 · DOI

• IntroductionHigh-quality anthropometric data is essential to creating effective nutrition policy, but theres limited evidence on the quality of data from population-based household surveys in India, particularly at the sub-national level.

  The evolution of anthropometric data quality methods and outcomes from 1993 to 2021 in the Comprehensive National Nutrition Survey and five rounds of the National Family Health Survey · 2026 · DOI

• Several limitations should be considered when interpreting the findings of this study. The study was conducted exclusively in lower secondary schools administered by the city of Trnava and participating in the municipal programme “Trnava in motion”. Schools were therefore not randomly selected but included based on their involvement in the programme. Consequently, the study used a non-probability, programme-based convenience sampling strategy at the school level. This limits the representativeness of the sample, and the findings cannot be generalised to all lower secondary school pupils in Trnava or to the wider population of children and adolescents in Slovakia. An important limitation relates to the sampling strategy and data availability. From the initial sample of 1,159 pupils, only 444 were included in the final analysis following data cleaning procedures. A substantial proportion of participants was excluded, primarily due to missing or incomplete data, as well as the exclusion of two schools with insufficient data quality. Although these exclusions were driven mainly by data completeness rather than 28 Vojteková et al. / J Nurs Soc Stud Public Health Rehabil predefined participant characteristics, the lack of detailed comparison between included and excluded pupils means that selection bias cannot be fully ruled out. Another limitation is the cross sectional design of the study, which does not allow causal relationships between the examined variables to be established. The identified associations between body composition, motor performance, and reaction performance should therefore be interpreted as relational rather than causal. Further limitations arise from the measurement of reaction performance. The INDEX_YN test primarily assesses reaction speed, attention, and response flexibility under time pressure, rather than broader or higher-order cognitive functions. Moreover, the operationalisation of slower reaction performance was based on the sample mean, reflecting a relative classification within the study population rather than clinically validated or standardised thresholds. This limits the interpretability of the findings and their comparability with studies assessing broader cognitive functioning. In addition, we interpret certain results of the regression analyses with caution. In the obesity model, some estimates, particularly those related to differences between schools, were characterised by wide confidence intervals, indicating limited precision and potential instability.

  Body composition, motor performance, and reaction performance in lower secondary school pupils in Trnava, Slovakia: a cross-sectional study · 2026 · DOI

• Future research should consider longitudinal designs to better understand causal relationships and incorporate objective dietary assessment methods. Additionally, the study did not account for other potential confounding levels, parental variables such as physical activity influence, or food availability, which could impact dietary adherence.

  Socioeconomic, Behavioral, and Anthropometric Determinants of Mediterranean Diet Quality Among Turkish Adolescents: A Cross-Sectional Study · 2026 · DOI

• These findings suggest that BMI may be an important factor in asthma control, while its relationship with physical activity levels warrants further investigation in pediatric asthma populations.

  Association of Obesity with Asthma Control and Physical Activity in Children with Asthma: A Cross-Sectional Pilot Study · 2026 · DOI

• Drawing on twenty-seven consecutive waves of the U.S. NHIS (1997–2023), the study leveraged a large, nationally representative sample to maximize statistical power and external validity while stratifying by age, sex, race, family structure, and so on to delineate associations between obesity-related asthma and neurodevelopmental disorders. this reverse causation, the cross-sectional design of Despite these strengths, the study has limitations. First, we acknowledge that study precludes establishing the temporal sequence between obesity and asthma onset, and therefore cannot distinguish whether obesity preceded asthma, asthma preceded obesity, or both developed concurrently. The cross-sectional design precludes determination of temporal sequence, and the observed associations may reflect residual or unmeasured confounding, or common underlying factors rather than causal effects of obesity and/or asthma on neurodevelopmental outcomes. The cross-sectional design precluded causal inference, and that residual confounding and multiple testing remain possible sources of bias. Additionally, data in the NHIS database are selfreported via questionnaires that may suffer recall bias. Also, the study did not control for potential confounding factors such as genetics and environment, which could bias the observed associations and weaken the robustness of the estimates. Furthermore, sparse data in several strata yielded imprecise estimates with wide confidence intervals, raising potential concerns about type I or type II errors. Finally, this study did not collect or analyze any biological data related to the proposed including inflammatory biomarkers, gut mechanistic pathways, microbiota profiles, or metabolic markers. Therefore, we cannot validate the biological mechanisms hypothesized to underlie the observed association between obesity-related asthma and neurodevelopmental disorders, and all related discussion is speculative and hypothesis-generating only.

  The impact of obesity-related asthma on neurodevelopmental disorders in children: a cross-sectional study · 2026 · DOI

• Our study possesses several relevant strengths. To our knowledge, it is the only study to provide detailed data on obesity prevalence and relevant determinants among university students in Germany. The sample is large and representative of the German university student population concerning state of residence, employment status, income, type of institution, and term of enrollment, enhancing generalizability. Data collection was supported by multiple quality assurance measures, contributing to the robustness of findings. This study also has several limitations. First, it relies on self-reported data for weight and height, which may introduce reporting biases. Second, we use BMI as the primary criterion for defining obesity, despite recognized limitations in its ability to reflect overall health accurately. Accordingly, we used the cutoff of 30 kg/m2 to classify students with obesity and to approach correlations with that measurement. Therefore, we cannot exclude that some individuals may have a larger BMI due to a higher lean-mass proportion, for example. Finally, the study’s cross-sectional design restricts our capacity to infer causality between the identified determinants and obesity, limiting conclusions to associations rather than cause-and-effect relationships.

  Obesity, food habits and socio-demographic factors among university students in Germany: a cross-sectional study · 2026 · DOI

• Our study has strengths related to its scope, data and methods. We conducted an analysis and presentation of trends in obesity that went beyond the traditional narrative of long-term increase and systematically quantified highly heterogeneous temporal dynamics. We used a large amount of population-based data, from countries covering more than 99% of the population of the world. We maintained a high standard of data quality through repeated checks of the study sample and characteristics, and did not use self-reported data to avoid bias. Data were analysed according to a consistent protocol. We used a statistical model that accounted for the age patterns of BMI during childhood, adolescence and adulthood. We used all available data while giving more weight to national data than to subnational and community data. As with all global analyses, our study has limitations.

  Obesity rise plateaus in developed nations and accelerates in developing nations · 2026 · DOI

• Food industry responsibility for developing healthier products with reduced sugar, salt, and trans fats is recommended but no market analysis or product innovation pipeline data for the Indian food industry is presented. Research comparing nutrient profiles of foods marketed to Indian adolescents versus international standards and innovation rates in healthier product development is missing.

  FOOD HABITS AND THE EMERGING HEALTH CRISIS AMONG INDIAN STUDENTS: AN ANALYTICAL STUDY OF CAUSES, EFFECTS AND IMPACT · 2026 · DOI

• The paper states parental influence on home-cooked meals and monitoring of food selections is critical but provides no framework for measuring parental efficacy, food literacy, or home food environment quality. Research is needed to quantify the relationship between specific parental behaviors (meal frequency monitoring, home cooking frequency, nutritional knowledge) and student dietary outcomes in Indian households.

  FOOD HABITS AND THE EMERGING HEALTH CRISIS AMONG INDIAN STUDENTS: AN ANALYTICAL STUDY OF CAUSES, EFFECTS AND IMPACT · 2026 · DOI

• Front-of-pack labeling and taxation policies on unhealthy foods are proposed for government intervention but no modeling studies exist estimating price elasticity of demand or consumption reduction rates specific to Indian student populations and food market conditions. Research must quantify the actual impact of taxation and labeling interventions on processed food purchasing behavior among Indian adolescents.

  FOOD HABITS AND THE EMERGING HEALTH CRISIS AMONG INDIAN STUDENTS: AN ANALYTICAL STUDY OF CAUSES, EFFECTS AND IMPACT · 2026 · DOI

• School canteen restrictions on high-energy, high-sugar, high-salt (HFSS) foods and nutrition education programs are recommended, but the paper contains no evidence comparing effectiveness across different school types (government, private, urban, rural). Implementation efficacy studies measuring behavior change outcomes before/after HFSS restrictions and nutrition education interventions in Indian schools are absent.

  FOOD HABITS AND THE EMERGING HEALTH CRISIS AMONG INDIAN STUDENTS: AN ANALYTICAL STUDY OF CAUSES, EFFECTS AND IMPACT · 2026 · DOI

• The study documents correlations between unhealthy eating, sedentary activities, and health conditions (obesity, fatigue, stress, digestive problems) but lacks longitudinal data on causal pathways. Prospective cohort studies tracking Indian students over 2-5 years are needed to establish temporal sequence and dose-response relationships between dietary behavior changes and chronic lifestyle-related disease development.

  FOOD HABITS AND THE EMERGING HEALTH CRISIS AMONG INDIAN STUDENTS: AN ANALYTICAL STUDY OF CAUSES, EFFECTS AND IMPACT · 2026 · DOI

• The paper identifies academic pressure and digital influence as critical factors in food preferences but provides no quantitative measurement methodology for these constructs. Future research must develop validated scales to measure academic stress intensity and digital food environment exposure (social media advertising frequency, influencer marketing exposure) in relation to fast food consumption among Indian adolescents.

  FOOD HABITS AND THE EMERGING HEALTH CRISIS AMONG INDIAN STUDENTS: AN ANALYTICAL STUDY OF CAUSES, EFFECTS AND IMPACT · 2026 · DOI

• The study examines food habits among Indian students but does not specify comparative analysis across different socioeconomic strata, urban versus rural settings, or regional variations in dietary patterns. Research is needed to isolate how urbanization intensity, regional food culture, and household income levels distinctly influence processed food consumption and nutritional outcomes among Indian student populations.

  FOOD HABITS AND THE EMERGING HEALTH CRISIS AMONG INDIAN STUDENTS: AN ANALYTICAL STUDY OF CAUSES, EFFECTS AND IMPACT · 2026 · DOI

• Conclusions and implications This study has several strengths and limitations. The large sample of children and parents and the variety of measurement types (both photographs and self-reported) strengthen the findings. Other strong aspects include the use of validated existing questionnaires that were The nutrition policy component of the Dutch intervention Jump-in significantly improved children’s at-school dietary behavior through higher consumption of water, milk, fruit, vegetables, and whole-wheat bread, and lower consumption of sweetened beverages, unhealthy snacks, and white bread for lunch. These findings may inform policy discussions on ways that best support healthy child at-school dietary behav- ior and demonstrate that, whatever form an HPS approach may take, a healthy nutrition policy component is a valuable addition. Acknowledgements The authors would like to thank all involved HPS professionals of the GGD Amsterdam for their help with data col- lection. Moreover, we thank all primary schools that participated, in particular the contact persons who greatly helped us in setting up the data collection. Similarly, we are very grateful to everyone who works or has worked on the creation and/or implementation of the Jump-in intervention. Lastly, we would like to thank Jobien Groen, Esmee Oude Geerdink, Malou Friedhoff, Simone Janssen, Valerie Tijhuis, Virginie Domsdorf and Jump-in Health Promotion Professionals for their help in conducting data collection. In particular we would like to thank Manon van Eijsden for her work in setting up this study. Without all these partners, the current study would not have been possible. Authors’ contributions MC was responsible for the conceptualization and funding acquisition. FT and VB were involved with the investiga- tion process. All authors were responsible for the methodology and project administration. VB and FT were responsible for the data cura- tion and performed the formal analyses. Supervision was provided by MC, VB and JU. VB and FT wrote the initial draft of the manuscript, which was revised and approved by all authors. Funding This work was supported by the Public Health Service (GGD) of Amsterdam without any research restrictions or (in)direct involve- ment in the study. Data availability Data are available on reasonable request, meaning that individual participant data and the intervention implementation scores that underlie the results reported in this article may be shared after de-identification to researchers who provide a methodologically sound proposal and whose proposed use of the data has been approved by the study’s authors and partners who provided the data. Code availability Not applicable.

  Effects of the Dutch Jump-in school nutrition policy intervention on children’s at-school dietary behavior · 2026 · DOI

• CONCLUSION AND IMPLICATIONS: Lack of standardized assessment, large variability in program characteristics, and insufficient intervention description made it difficult to discern best practices for children's cooking programs.

  Outcomes of Children's Cooking Programs: A Systematic Review of Intervention Studies · 2024 · DOI

• Engaging children and adolescents in multiple phases of research on paediatric obesity is beneficial in allowing better insight into their perspectives and providing recommendations that are more in line with their personal needs and life circumstances; such studies are still scarce in this field, however.

  HOW ARE CHILDREN AND YOUNG PEOPLE ENGAGED IN RESEARCH ON PAEDIATRIC OBESITY AND WHICH ISSUES DO THEY REPORT? A SCOPING REVIEW · 2023 · DOI

• Although the implications of changes in diets, lifestyles, and food environments have been examined, the specific role of excess calorie availability (ECA)—understood as calorie availability in excess of human requirements for a healthy life—and the cohort mechanisms that underlie trends in adult body mass index (BMI) are poorly understood.

  Excess calorie availability and adult BMI: A cohort analysis of patterns and trends for 156 countries from 1890 to 2015 · 2022 · DOI

• When traditional measures for material and economic welfare are scarce or unreliable, height and the body mass index (BMI) are now widely accepted measures that represent cumulative and current net nutrition in development studies.

  Weight and economic development: current net nutrition in the late 19th- and early 20th-century United States · 2020 · DOI

Most-cited papers in Obesity, Physical Activity, Diet

• Health Effects of Overweight and Obesity in 195 Countries over 25 Years · New England Journal of Medicine · 2017 · 6,562 citations
• The Physical Activity Guidelines for Americans · JAMA · 2018 · 5,373 citations
• The Spread of Obesity in a Large Social Network over 32 Years · New England Journal of Medicine · 2007 · 3,664 citations
• Expert Committee Recommendations Regarding the Prevention, Assessment, and Treatment of Child and Adolescent Overweight and Obesity: Summary Report · PEDIATRICS · 2007 · 3,405 citations
• Association of All-Cause Mortality With Overweight and Obesity Using Standard Body Mass Index Categories · JAMA · 2013 · 3,335 citations
• A review of correlates of physical activity of children and adolescents · Medicine & Science in Sports & Exercise · 2000 · 2,641 citations
• Worldwide trends in underweight and obesity from 1990 to 2022: a pooled analysis of 3663 population-representative studies with 222 million children, adolescents, and adults · The Lancet · 2024 · 1,878 citations
• Health Consequences of Obesity in Youth: Childhood Predictors of Adult Disease · PEDIATRICS · 1998 · 1,685 citations
• Obesity in adults: a clinical practice guideline · Canadian Medical Association Journal · 2020 · 1,210 citations
• Longitudinal tracking of adolescent smoking, physical activity, and food choice behaviors. · American Journal of Public Health · 1994 · 949 citations

Most recent work

• Obesity rise plateaus in developed nations and accelerates in developing nations · Nature · 2026
• Metabolic Risk Factors Are Associated With Weight Status Change Over Four Years in Children Aged 4–6 Years With Obesity · Acta Paediatrica · 2026
• Physical activity and sedentary behavior among adolescents in the Visegrad Group countries: a cross-country comparison · Health Problems of Civilization · 2026
• Family social support and meeting the physical activity recommendations in adolescents · International Journal of Health Promotion and Education · 2026
• DAGIS Salo cohort profile: a longitudinal and cross-sectional study to identify environmental and individual factors linked to health behaviours, recovery from stress, weight and learning outcomes among Finnish schoolchildren · BMC Public Health · 2026
• Effects of the Dutch Jump-in school nutrition policy intervention on children’s at-school dietary behavior · Journal of Public Health · 2026
• FOOD HABITS AND THE EMERGING HEALTH CRISIS AMONG INDIAN STUDENTS: AN ANALYTICAL STUDY OF CAUSES, EFFECTS AND IMPACT · INTERNATIONAL JOURNAL OF PUBLIC HEALTH RESEARCH AND DEVELOPMENT · 2026
• Hábitos alimenticios y riesgo cardiometabólico en adolescentes: un análisis mediante regresión logística binaria · Revista Hospital Medicine and Clinical Management · 2026
• Experiential learning for nutrition literacy of school-aged children: a study protocol of cluster randomized controlled trial · BMC Public Health · 2026
• Development and validation of an explainable machine learning-based risk prediction model for obesity in Chinese children and adolescents: a population-based study · Frontiers in Nutrition · 2026

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