title: A randomised-controlled trial of the effects of very low-carbohydrate and high-carbohydrate diets on cognitive performance in patients with type 2 diabetes.
abstract: 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.
authors.affiliation: 1Commonwealth Scientific and Industrial Research Organisation (CSIRO) - Health and Biosecurity,Adelaide,SA 5000,Australia.
authors.forename: Jeannie
authors.initials: J
authors.lastname: Tay
authors.affiliation: 1Commonwealth Scientific and Industrial Research Organisation (CSIRO) - Health and Biosecurity,Adelaide,SA 5000,Australia.
authors.forename: Ian T
authors.initials: IT
authors.lastname: Zajac
authors.affiliation: 2Discipline of Medicine,University of Adelaide,Adelaide, SA 5000,Australia.
authors.forename: Campbell H
authors.initials: CH
authors.lastname: Thompson
authors.affiliation: 1Commonwealth Scientific and Industrial Research Organisation (CSIRO) - Health and Biosecurity,Adelaide,SA 5000,Australia.
authors.forename: Natalie D
authors.initials: ND
authors.lastname: Luscombe-Marsh
authors.affiliation: 1Commonwealth Scientific and Industrial Research Organisation (CSIRO) - Health and Biosecurity,Adelaide,SA 5000,Australia.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Danthiir
authors.affiliation: 1Commonwealth Scientific and Industrial Research Organisation (CSIRO) - Health and Biosecurity,Adelaide,SA 5000,Australia.
authors.forename: Manny
authors.initials: M
authors.lastname: Noakes
authors.affiliation: 4Alliance for Research in Exercise, Nutrition and Activity (ARENA),Sansom Institute for Health Research,University of South Australia,Adelaide,SA 5001,Australia.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Buckley
authors.affiliation: 2Discipline of Medicine,University of Adelaide,Adelaide, SA 5000,Australia.
authors.forename: Gary A
authors.initials: GA
authors.lastname: Wittert
authors.affiliation: 1Commonwealth Scientific and Industrial Research Organisation (CSIRO) - Health and Biosecurity,Adelaide,SA 5000,Australia.
authors.forename: Grant D
authors.initials: GD
authors.lastname: Brinkworth
keywords:  DSST digit symbol substitution;  HC high carbohydrate;  LC very low-carbohydrate;  T2D type 2 diabetes;  high-unsaturated/low-saturated-fat diet;  low-fat diet; Cognitive performance; Diabetes; Glycaemic control; Macronutrient composition; Weight loss