Pre-diabetes: high glycaemic diet blunts exercise-induced improvements in glucose effectiveness

  • Hari A & al.
  • Acta Diabetol
  • 5 Jan 2019

  • curated by Antara Ghosh
  • UK Clinical Digest
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  • Glycaemic index (GI) of the diet might influence enhancing effect of exercise (Ex) on glucose effectiveness in adults with pre-diabetes.
  • High GI diet might suppress Ex-induced enhancement of glucose effectiveness, which could be mediated through plasma free fatty acid.
  • A clear enhancing effect of Ex on glucose effectiveness was observed in patients receiving low GI diet.

Why this matters

  • Findings indicate towards better counselling of patients for adoption of a healthier lifestyle for primary prevention of cardio-metabolic disorders.
  • Information regarding effect of GI diet on Ex-induced changes to glucose effectiveness in individuals with prediabetes is limited.

Study design

  • Total of 33 older sedentary participants (65.7±4.3 years) with obesity and oral glucose tolerance test-confirmed prediabetes were evaluated.
  • Participants were recruited to a 12-week Ex training programme (1 hour/day, 5 days/week at ~85% of maximum heart rate) and were randomly allocated to receive either a concurrent low ([Ex-LG]; 40±0.3 au) or high ([Ex-HG]; 80±0.6 au) GI diet.
  • Funding: NIH.

Key results

  • Baseline glucose effectiveness was similar in Ex-HG and Ex-LG but increased by ~20% post-intervention in the Ex-LG arm (P<.05>
  • Plasma free fatty acid concentrations also decreased significantly by ~28% only in the Ex-LG arm (change from baseline, 0.13±0.23 mmol/L; P<.05>
  • Fasting hepatic glucose production decreased only in Ex-LG arm (P<.05>
  • Improvement in weight, cardiorespiratory fitness and clamp-measured peripheral insulin resistance was similar in both arms.


  • Small study population.
  • Glucose effectiveness not measured by the gold standard graded hyperglyacemic pancreatic clamp.

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