Skip to main content
    • Aa
    • Aa

A randomised-controlled trial of the effects of very low-carbohydrate and high-carbohydrate diets on cognitive performance in patients with type 2 diabetes

  • Jeannie Tay (a1) (a2) (a3), Ian T. Zajac (a1), Campbell H. Thompson (a2), Natalie D. Luscombe-Marsh (a1), Vanessa Danthiir (a1), Manny Noakes (a1), Jonathan D. Buckley (a4), Gary A. Wittert (a2) and Grant D. Brinkworth (a1)...

This study compared the longer-term effects of a very low-carbohydrate, high-fat diet with a high-carbohydrate, low-fat diet on cognitive performance in individuals with type 2 diabetes (T2D). In total, 115 obese adults with T2D (sixty-six males, BMI: 34·6 (sd 4·3) kg/m2, age: 58 (sd 7) years, HbA1c: 7·3 (sd 1·1) %, diabetes duration: 8 (sd 6) years) were randomised to consume either an energy-restricted, very low-carbohydrate, low-saturated-fat (LC) diet or an energy-matched high unrefined carbohydrate, low-fat (HC) diet with supervised aerobic/resistance exercise (60 min, 3 d/week) for 52 weeks. Body weight, HbA1c and cognitive performance assessing perceptual speed, reasoning speed, reasoning ability, working memory, verbal fluency, processing speed, short-term memory, inhibition and memory scanning speed were assessed before and after intervention. No differences in the changes in cognitive test performance scores between the diet groups were observed for any of the cognitive function outcomes assessed (P≥0·24 time×diet). Percentage reduction in body weight correlated with improvements with perceptual speed performance. In obese adults with T2D, both LC and HC weight-loss diets combined with exercise training had similar effects on cognitive performance. This suggests that an LC diet integrated within a lifestyle modification programme can be used as a strategy for weight and diabetes management without the concern of negatively affecting cognitive function.

Corresponding author
* Corresponding author: Associate Professor G. D. Brinkworth, fax +61 8 8303 8899, email
Linked references
Hide All

This list contains references from the content that can be linked to their source. For a full set of references and notes please see the PDF or HTML where available.

1. AB Evert , JL Boucher , M Cypress , et al. (2013) Nutrition therapy recommendations for the management of adults with diabetes. Diabetes Care 36, 38213842.

2. WS Yancy Jr, EC Westman , JR McDuffie , et al. (2010) A randomized trial of a low-carbohydrate diet vs orlistat plus a low-fat diet for weight loss. Arch Intern Med 170, 136145.

3. O Ajala , P English & J Pinkney (2013) Systematic review and meta-analysis of different dietary approaches to the management of type 2 diabetes. Am J Clin Nutr 97, 505516.

4. J Tay , ND Luscombe-Marsh , CH Thompson , et al. (2015) Comparison of low- and high-carbohydrate diets for type 2 diabetes management: a randomized trial. Am J Clin Nutr 102, 780790.

5. CC Chung , D Pimentel , AJ Jor’dan , et al. (2015) Inflammation-associated declines in cerebral vasoreactivity and cognition in type 2 diabetes. Neurology 85, 450458.

6. T Cukierman , HC Gerstein & JD Williamson (2005) Cognitive decline and dementia in diabetes – systematic overview of prospective observational studies. Diabetologia 48, 24602469.

7. GJ Biessels , IJ Deary & CM Ryan (2008) Cognition and diabetes: a lifespan perspective. Lancet Neurol 7, 184190.

9. TC Crowe (2005) Safety of low-carbohydrate diets. Obes Rev 6, 235245.

10. GD Brinkworth , JD Buckley , M Noakes , et al. (2009) Long-term effects of a very low-carbohydrate diet and a low-fat diet on mood and cognitive function. Arch Intern Med 169, 18731880.

11. A Makris , VL Darcey , DL Rosenbaum , et al. (2013) Similar effects on cognitive performance during high- and low-carbohydrate obesity treatment. Nutr Diabetes 3, e89.

12. HW Rodbard , L Blonde , SS Braithwaite , et al. (2007) American Association of Clinical Endocrinologists medical guidelines for clinical practice for the management of diabetes mellitus. Endocr Pract 13, Suppl. 1, 168.

17. V Danthiir , D Hosking , NR Burns , et al. (2014) Cognitive performance in older adults is inversely associated with fish consumption but not erythrocyte membrane n-3 fatty acids. J Nutr 144, 311320.

18. A Hoyland , CL Lawton & L Dye (2008) Acute effects of macronutrient manipulations on cognitive test performance in healthy young adults: a systematic research review. Neurosci Biobehav Rev 32, 7285.

19. E van den Berg , RP Kloppenborg , RP Kessels , et al. (2009) Type 2 diabetes mellitus, hypertension, dyslipidemia and obesity: a systematic comparison of their impact on cognition. Biochim Biophys Acta 1792, 470481.

21. F Faul , E Erdfelder , A Buchner , et al. (2009) Statistical power analyses using G*Power 3.1: tests for correlation and regression analyses. Behav Res Methods 41, 11491160.

22. J Cohen (1988) Statistical Power Analysis for the Behavioral Sciences, 2nd ed. New York: Academic Press.

23. KE D’Anci , KL Watts , RB Kanarek , et al. (2009) Low-carbohydrate weight-loss diets. Effects on cognition and mood. Appetite 52, 96103.

25. MM Machulda , VS Pankratz , TJ Christianson , et al. (2013) Practice effects and longitudinal cognitive change in normal aging vs. incident mild cognitive impairment and dementia in the Mayo Clinic Study of Aging. Clin Neuropsychol 27, 12471264.

26. E van den Berg , YD Reijmer , J de Bresser , et al. (2010) A 4 year follow-up study of cognitive functioning in patients with type 2 diabetes mellitus. Diabetologia 53, 5865.

27. C Lowe & P Rabbitt (1998) Test/re-test reliability of the CANTAB and ISPOCD neuropsychological batteries: theoretical and practical issues. Cambridge Neuropsychological Test Automated Battery. International Study of Post-Operative Cognitive Dysfunction. Neuropsychologia 36, 915923.

28. YK Chang , CY Pan , FT Chen , et al. (2012) Effect of resistance-exercise training on cognitive function in healthy older adults: a review. J Aging Phys Act 20, 497517.

29. L Bherer , KI Erickson & T Liu-Ambrose (2013) A review of the effects of physical activity and exercise on cognitive and brain functions in older adults. J Aging Res 2013, 657508.

30. SJ Blondell , R Hammersley-Mather & JL Veerman (2014) Does physical activity prevent cognitive decline and dementia?: a systematic review and meta-analysis of longitudinal studies. BMC Public Health 14, 510.

31. AV Witte , M Fobker , R Gellner , et al. (2009) Caloric restriction improves memory in elderly humans. Proc Natl Acad Sci U S A 106, 12551260.

32. AL Christman , K Matsushita , RF Gottesman , et al. (2011) Glycated haemoglobin and cognitive decline: the Atherosclerosis Risk in Communities (ARIC) study. Diabetologia 54, 16451652.

33. WJ Hoyer , RS Stawski , C Wasylyshyn , et al. (2004) Adult age and digit symbol substitution performance: a meta-analysis. Psychol Aging 19, 211214.

34. N Awad , M Gagnon & C Messier (2004) The relationship between impaired glucose tolerance, type 2 diabetes, and cognitive function. J Clin Exp Neuropsychol 26, 10441080.

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

British Journal of Nutrition
  • ISSN: 0007-1145
  • EISSN: 1475-2662
  • URL: /core/journals/british-journal-of-nutrition
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Altmetric attention score

Full text views

Total number of HTML views: 24
Total number of PDF views: 258 *
Loading metrics...

Abstract views

Total abstract views: 1895 *
Loading metrics...

* Views captured on Cambridge Core between 23rd November 2016 - 26th July 2017. This data will be updated every 24 hours.