The Effect of a Diet Moderately High in Protein and Fiber on Insulin Sensitivity Measured Using the Dynamic Insulin Sensitivity and Secretion Test (DISST).

Lisa Te Morenga,Sheila Williams,Jim Mann,Paul Docherty

doi:10.3390/nu9121291

Lisa Te Morenga, Sheila Williams + Show 2 more

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https://doi.org/10.3390/nu9121291

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Abstract

Evidence shows that weight loss improves insulin sensitivity but few studies have examined the effect of macronutrient composition independently of weight loss on direct measures of insulin sensitivity. We randomised 89 overweight or obese women to either a standard diet (StdD), that was intended to be low in fat and relatively high in carbohydrate (n = 42) or to a relatively high protein (up to 30% of energy), relatively high fibre (>30 g/day) diet (HPHFib) (n = 47) for 10 weeks. Advice regarding strict adherence to energy intake goals was not given. Insulin sensitivity and secretion was assessed by a novel method—the Dynamic Insulin Sensitivity and Secretion Test (DISST). Although there were significant improvements in body composition and most cardiometabolic risk factors on HPHFib, insulin sensitivity was reduced by 19.3% (95% CI: 31.8%, 4.5%; p = 0.013) in comparison with StdD. We conclude that the reduction in insulin sensitivity after a diet relatively high in both protein and fibre, despite cardiometabolic improvements, suggests insulin sensitivity may reflect metabolic adaptations to dietary composition for maintenance of glucose homeostasis, rather than impaired metabolism.

Highlights

There is considerable evidence to show that weight loss can improve insulin sensitivity and reduce the risk of diabetes and cardiovascular disease (CVD) [1,2]
There is a substantial body of literature to show that variations in the macronutrient composition of diets can modify the cardiometabolic abnormalities associated with insulin resistance (IR) and reduce the risk of diabetes
More participants were initially randomised to the high protein and high fibre diet (HPHFib) group (44 vs. 39), they were slightly older and had a higher estimated prevalence of insulin resistance

Summary

Introduction

There is considerable evidence to show that weight loss can improve insulin sensitivity and reduce the risk of diabetes and cardiovascular disease (CVD) [1,2]. There is a substantial body of literature to show that variations in the macronutrient composition of diets can modify the cardiometabolic abnormalities associated with insulin resistance (IR) and reduce the risk of diabetes. High protein diets have become a popular approach to weight loss and improving body composition, Nutrients 2017, 9, 1291; doi:10.3390/nu9121291 www.mdpi.com/journal/nutrients. An alternative approach to reducing the metabolic abnormalities associated with low fat, high carbohydrate diets is to modify the quality of the carbohydrate consumed. There is some experimental and much epidemiological evidence to suggest that high fibre ( soluble fibre), low glycemic index (GI) carbohydrates, derived from minimally processed wholegrain cereals, fruit, vegetables and legumes may improve insulin sensitivity, maintain glucose homeostasis, reduce postprandial insulin concentrations, and reduce blood pressure in comparison with refined and high GI carbohydrates [6]

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