Abstract
Continuous glucose monitors (CGMs) provide detailed glucose profiles, but their relevance to health outcomes in individuals without diabetes remains unclear. Here we assess time in range (TIR3.9–5.6 and TITR3.9-7.8) and glycaemic variability in individuals (N = 3,634; age 46 ± 12 y; 83% female; BMI 27 ± 6 kg/m²) from PREDICT 1 (NCT03479866), PREDICT 2 (NCT03983733), and PREDICT 3 (NCT04735835) without diabetes or prediabetes, and explore associations with demographic, diet, lifestyle, cardiometabolic markers, and predicted cardiovascular risk. Outcomes are non-pre-defined exploratory analyses. Higher TIR3.9–5.6 is associated with lower HbA1c, OGTT glucose, carbohydrate intake, and higher protein intake. Sleep duration is inversely correlated with mean glucose. TIR3.9–5.6 provided moderate discrimination for predicted ASCVD 10-year risk (AUC = 0.75). While CGM metrics show potential to capture some components of glycaemic physiology, longer-term health outcomes are required to demonstrate whether CGM monitoring has utility for health management in euglycaemic individuals.
Similar content being viewed by others
Data availability
The study data can be released to bona fide researchers who submit a research proposal to data.papers@joinzoe.com. All proposals will be reviewed by a sub-panel of the ZOE Scientific Advisory Board within four working weeks. To protect participant privacy, individual participant clinical data are not publicly available and cannot be deposited in public repositories. Proposals, researchers or institutions requesting data will be approved if they meet the standard criteria related to ethics, privacy and data protection regulations. Approved researchers are required to enter into a data-sharing agreement with ZOE.
Code availability
The scripts for the statistical analysis are freely available upon request to ZOE Ltd. Code will be made available within 2 months of the request. Code requests should be sent to data.papers@joinzoe.com.
References
Cappon, G., Vettoretti, M., Sparacino, G. & Facchinetti, A. Continuous glucose monitoring sensors for diabetes management: a review of technologies and applications. Diab. Metab. J. 43, 383–397 (2019).
Danne, T. et al. International consensus on use of continuous glucose monitoring. Diab. Care 40, 1631–1640 (2017).
Liang, S. et al. Glucose variability for cardiovascular risk factors in type 2 diabetes: a meta-analysis. J. Diab. Metab. Disord. 16, 45 (2017).
Maiorino, M. I. et al. Effects of continuous glucose monitoring on metrics of glycemic control in diabetes: a systematic review with meta-analysis of randomized controlled trials. Diab. Care 43, 1146–1156 (2020).
Beck, R. W., Connor, C. G., Mullen, D. M., Wesley, D. M. & Bergenstal, R. M. The fallacy of average: how using HbA(1c) alone to assess glycemic control can be misleading. Diab. Care 40, 994–999 (2017).
Cui, X., Abduljalil, A., Manor, B. D., Peng, C. K. & Novak, V. Multi-scale glycemic variability: a link to gray matter atrophy and cognitive decline in type 2 diabetes. PLoS ONE 9, e86284 (2014).
Xie, P. et al. Time in range in relation to amputation and all-cause mortality in hospitalised patients with diabetic foot ulcers. Diab. Metab. Res Rev. 38, e3498 (2022).
Lu, J. et al. Time in range is associated with carotid intima-media thickness in type 2 diabetes. Diab. Technol. Ther. 22, 72–78 (2020).
Ning, F. et al. Development of coronary heart disease and ischemic stroke in relation to fasting and 2-hour plasma glucose levels in the normal range. Cardiovasc. Diabetol. 11, 76 (2012).
Chung, S. T. et al. Time to glucose peak during an oral glucose tolerance test identifies prediabetes risk. Clin. Endocrinol. 87, 484–491 (2017).
Narang, B. J., Atkinson, G., Gonzalez, J. T. & Betts, J. A. A tool to explore discrete-time data: the time series response analyser. Int. J. Sport Nutr. Exerc. Metab. 30, 374–381 (2020).
Chen, X., Merovci, A., DeFronzo, R. A. & Tripathy, D. Chronic physiologic hyperglycemia impairs insulin-mediated suppression of plasma glucagon concentration in healthy humans. Metabolism 142, 155512 (2023).
Shannon, C. E. et al. Effects of sustained hyperglycemia on skeletal muscle lipids in healthy subjects. J. Clin. Endocrinol. Metab. 107, e3177–e3185 (2022).
Shannon, C. et al. Effect of chronic hyperglycemia on glucose metabolism in subjects with normal glucose tolerance. Diabetes 67, 2507–2517 (2018).
Merovci, A. et al. Effect of mild physiologic hyperglycemia on insulin secretion, insulin clearance, and insulin sensitivity in healthy glucose-tolerant subjects. Diabetes 70, 204–213 (2021).
Ceriello, A. et al. Oscillating glucose is more deleterious to endothelial function and oxidative stress than mean glucose in normal and type 2 diabetic patients. Diabetes 57, 1349–1354 (2008).
Freckmann, G. et al. Continuous glucose profiles in healthy subjects under everyday life conditions and after different meals. J. Diab. Sci. Technol. 1, 695–703 (2007).
Mazze, R. S. et al. Characterizing glucose exposure for individuals with normal glucose tolerance using continuous glucose monitoring and ambulatory glucose profile analysis. Diab. Technol. Ther. 10, 149–159 (2008).
Zhou, J. et al. Reference values for continuous glucose monitoring in Chinese subjects. Diab. Care 32, 1188–1193 (2009).
Borg, R. et al. Real-life glycaemic profiles in non-diabetic individuals with low fasting glucose and normal HbA1c: the A1C-Derived Average Glucose (ADAG) Study. Diabetologia 53, 1608–1611 (2010).
Fox, L. A., Beck, R. W. & Xing, D. Variation of interstitial glucose measurements assessed by continuous glucose monitors in healthy, nondiabetic individuals. Diab. Care 33, 1297–1299 (2010).
Hill, N. R. et al. Normal reference range for mean tissue glucose and glycemic variability derived from continuous glucose monitoring for subjects without diabetes in different ethnic groups. Diab. Technol. Ther. 13, 921–928 (2011).
Shah, V. N. et al. Continuous glucose monitoring profiles in healthy nondiabetic participants: a multicenter prospective study. J. Clin. Endocrinol. Metab. 104, 4356–4364 (2019).
Derosa, G. et al. Continuous glucose monitoring system in free-living healthy subjects: results from a pilot study. Diab. Technol. Ther. 11, 159–169 (2009).
Jonas, D. E. et al. Screening for prediabetes and type 2 diabetes: updated evidence report and systematic review for the US Preventive Services Task Force. JAMA 326, 744–760 (2021).
Bowen, M. E., Xuan, L., Lingvay, I. & Halm, E. A. Performance of a random glucose case-finding strategy to detect undiagnosed diabetes. Am. J. Prev. Med. 52, 710–716 (2017).
Monnier, L., Colette, C. & Owens, D. R. Glycemic variability: the third component of the dysglycemia in diabetes. Is it important? How to measure it?. J. Diab. Sci. Technol. 2, 1094–1100 (2008).
Rhee, M. K. et al. Random plasma glucose predicts the diagnosis of diabetes. PLoS ONE 14, e0219964 (2019).
Keshet, A. et al. CGMap: characterizing continuous glucose monitor data in thousands of non-diabetic individuals. Cell Metab. 35, 758–769.e753 (2023).
Smith, H. A. & Betts, J. A. Nutrient timing and metabolic regulation. J. Physiol. 600, 1299–1312 (2022).
Smith, H. A., Gonzalez, J. T., Thompson, D. & Betts, J. A. Dietary carbohydrates, components of energy balance, and associated health outcomes. Nutr. Rev. 75, 783–797 (2017).
Smith, H. A. et al. Glucose control upon waking is unaffected by hourly sleep fragmentation during the night, but is impaired by morning caffeinated coffee. Br. J. Nutr. 124, 1114–1120 (2020).
Smith, H. A. et al. Characterising 24-h skeletal muscle gene expression alongside metabolic & endocrine responses under diurnal conditions. J. Clin. Endocrinol. Metab. 110, e1017–e1030 (2024).
Smith, H. A. et al. Whey protein-enriched and carbohydrate-rich breakfasts attenuate insulinaemic responses to an ad-libitum lunch relative to extended morning fasting; a randomised crossover trial. J. Nutr. 153, 2842–2853 (2023).
Smith, H. A. et al. Whey protein-enriched and carbohydrate-rich breakfasts attenuate insulinemic responses to an ad libitum lunch relative to extended morning fasting: a randomized crossover trial. J. Nutr. 153, 2842–2853 (2023).
Tsereteli, N. et al. Impact of insufficient sleep on dysregulated blood glucose control under standardised meal conditions. Diabetologia 65, 356–365 (2022).
Berry, S. et al. Personalised REsponses to DIetary Composition Trial (PREDICT): an intervention study to determine inter-individual differences in postprandial response to foods. Protoc. Exchange (2020). Available at: https://www.protocols.io/view/personalised-responses-to-dietary-composition-tria-261gerw3dl47/v1.
Berry, S. E. et al. Human postprandial responses to food and potential for precision nutrition. Nat. Med. 26, 964–973 (2020).
Goff, D. C. Jr. et al. 2013 ACC/AHA guideline on the assessment of cardiovascular risk: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation 129, S49–S73 (2014).
Atabaki-Pasdar, N. et al. Predicting and elucidating the etiology of fatty liver disease: a machine learning modeling and validation study in the IMI DIRECT cohorts. PLoS Med. 17, e1003149 (2020).
Bingham, S. A. et al. Nutritional methods in the European Prospective Investigation of Cancer in Norfolk. Public Health Nutr. 4, 847–858 (2001).
PH, England. McCance and Widdowsons Composition of Foods Integrated Dataset. (Public Health England, London, 2021).
Satija, A. et al. Plant-based dietary patterns and incidence of type 2 diabetes in US men and women: results from three prospective cohort studies. PLoS medicine. 13, 6 (2016).
Santos, F. S. D. et al. Nova diet quality scores and risk of weight gain in the NutriNet Brasil cohort study. Public Health Nutr. 26, 2366–2373 (2023).
de Castro, J. M. Accommodation of particular foods or beverages into spontaneously ingested evening meals. Appetite 23, 57–66 (1994).
Betts, J. A. et al. Bath Breakfast Project (BBP) - examining the role of extended daily fasting in human energy balance and associated health outcomes: Study protocol for a randomised controlled trial ISRCTN31521726. Trials 12, 12 (2011).
Kant, A. K. & Graubard, B. I. Within-person comparison of eating behaviors, time of eating, and dietary intake on days with and without breakfast: NHANES 2005-2010. Am. J. Clin. Nutr. 102, 661–670 (2015).
Bermingham, K. M. et al. Snack quality and snack timing are associated with cardiometabolic blood markers: the ZOE PREDICT study. Eur. J. Nutr. 63, 121–133 (2023).
van Hees, V. T. et al. Estimating sleep parameters using an accelerometer without sleep diary. Sci. Rep. 8, 12975 (2018).
Westerterp, K. R. Diet induced thermogenesis. Nutr. Metab. 1, 5 (2004).
Rikhi, R. & Shapiro, M. D. Assessment of atherosclerotic cardiovascular disease risk in primary prevention. J. Cardiopulm. Rehabil. Prev. 42, 397–403 (2022).
Chia, C. W., Egan, J. M. & Ferrucci, L. Age-related changes in glucose metabolism, hyperglycemia, and cardiovascular risk. Circ. Res. 123, 886–904 (2018).
Esteghamati, A. et al. Optimal cut-off of homeostasis model assessment of insulin resistance (HOMA-IR) for the diagnosis of metabolic syndrome: third national surveillance of risk factors of non-communicable diseases in Iran (SuRFNCD-2007). Nutr. Metab. 7, 26 (2010).
Lee, S. et al. Cutoff values of surrogate measures of insulin resistance for metabolic syndrome in Korean non-diabetic adults. J. Korean Med. Sci. 21, 695–700 (2006).
Lin, S. Y. et al. Optimal threshold of homeostasis model assessment of insulin resistance to identify metabolic syndrome in a chinese population aged 45 years or younger. Front. Endocrinol. 12, 746747 (2021).
Bartoli, E., Fra, G. P. & Carnevale Schianca, G. P. The oral glucose tolerance test (OGTT) revisited. Eur. J. Intern. Med. 22, 8–12 (2011).
Edinburgh, R. M., Betts, J. A., Burns, S. F. & Gonzalez, J. T. Concordant and divergent strategies to improve postprandial glucose and lipid metabolism. Nutr. Bull. 42, 113–122 (2017).
Smith, K. et al. Thrice daily consumption of a novel, premeal shot containing a low dose of whey protein increases time in euglycemia during 7 days of free-living in individuals with type 2 diabetes. BMJ Open Diabetes Res. Care 10, e002820 (2022).
Meng, H., Matthan, N. R., Ausman, L. M. & Lichtenstein, A. H. Effect of prior meal macronutrient composition on postprandial glycemic responses and glycemic index and glycemic load value determinations. Am. J. Clin. Nutr. 106, 1246–1256 (2017).
Van Dijk, J. W. et al. Exercise and 24-h glycemic control: equal effects for all type 2 diabetes patients?. Med. Sci. Sports Exerc. 45, 628–635 (2013).
Sparks, J. R. et al. Glycemic variability: Importance, relationship with physical activity, and the influence of exercise. Sports Med. Health Sci. 3, 183–193 (2021).
D’Souza, N. C. et al. The impact of sex, body mass index, age, exercise type and exercise duration on interstitial glucose levels during exercise. Sensors 23, 9059 (2023).
Donga, E. et al. A single night of partial sleep deprivation induces insulin resistance in multiple metabolic pathways in healthy subjects. J. Clin. Endocrinol. Metab. 95, 2963–2968 (2010).
Sweeney, E. L., Jeromson, S., Hamilton, D. L., Brooks, N. E. & Walshe, I. H. Skeletal muscle insulin signaling and whole-body glucose metabolism following acute sleep restriction in healthy males. Physiol Rep. 5, e13498 (2017).
Battelino, T. et al. Continuous glucose monitoring and metrics for clinical trials: an international consensus statement. Lancet Diab. Endocrinol. 11, 42–57 (2023).
Gado, M. et al. Sex-based differences in insulin resistance. J. Endocrinol. 261, 1 (2024).
Acknowledgements
This work was supported by ZOE Ltd and TwinsUK, which is funded by the Wellcome Trust, Medical Research Council, Versus Arthritis, European Union Horizon 2020, Chronic Disease Research Foundation (CDRF), ZOE Ltd and the National Institute for Health Research (NIHR) Clinical Research Network (CRN) and Biomedical Research Centre based at Guy’s and St Thomas’ NHS Foundation Trust in partnership with King’s College London. H.S.D. is supported by the National Institute of Health [grant number R00HL153795].
Author information
Authors and Affiliations
Contributions
K.M.B., H.A.S., and S.E.B. contributed equally to the conception, design, analysis, and drafting of the manuscript. S.E.B. and T.D.S. contributed to all aspects of the study except software development, including study design, data interpretation, and manuscript revision. R.D., G.H., and J.W. developed and provided the software and infrastructure that hosted the PREDICT data. E.L.D., J.T.G., A.M.V., P.W.F., L.M.D., H.S.D., and A.T.C. contributed to data interpretation and revisions of the manuscript.
Corresponding author
Ethics declarations
Competing interests
T.D.S., J.W. and G.H. are co-founders of ZOE Ltd. A.M.V., P.W.F., L.M.D., A.T.C. and T.D.S. are consultants to ZOE Ltd. K.M.B., H.A.S., R.D., G.H., S.E.B. and J.W. are or have been employees of ZOE Ltd. K.M.B., H.A.S., A.M.V., L.M.D., R.D., G.H., J.W., T.D.S. and S.E.B. also receive options in ZOE Ltd. The remaining authors declare no competing interests.
Peer review
Peer review information
Nature Communications thanks Diana Thomas and the other, anonymous, reviewers for their contribution to the peer review of this work. A peer review file is available.
Additional information
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
About this article
Cite this article
Bermingham, K.M., Smith, H.A., Duncan, E.L. et al. Associations of continuous glucose monitor derived time in range and glycaemic variability with diet lifestyle and demographics. Nat Commun (2026). https://doi.org/10.1038/s41467-026-70308-3
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41467-026-70308-3


