An evidence‐based approach to developing low‐carbohydrate diets for type 2 diabetes management: A systematic review of interventions and methods

Abstract

Aim To identify core diet and delivery components of low‐carbohydrate (CHO) diets that have demonstrated efficacy for type 2 diabetes (T2D) management. Materials and methods MEDLINE, Pre‐MEDLINE, EMBASE, CINAHL and the Cochrane Library of Controlled Trials databases were systematically searched from inception until August 18, 2018. Primary intervention studies of low‐CHO diets (≤130 g/d or 26% total energy intake [TEI]) were included. Content analysis was performed on the low‐CHO diet protocols classified as safe and effective for T2D management. Results A total of 41 studies published between 1963 and 2018 were included, of which 40 were classified as safe and effective for inclusion in the primary analysis. Thirteen studies (13/40) were on very‐low‐CHO diets (<50 g/d), 14/40 included low‐CHO diets (≤130 g/d or 26% TEI), and 13/40 were adapted according to participant progress. Thirty‐one studies reported a total energy prescription, of which 18/31 encouraged ad libitum intakes. Twenty studies reported a prescribed dietary fat amount, of which 18/20 were unrestricted or high‐fat (>35% TEI). Twenty‐six studies reported a prescribed dietary protein amount, of which 22 were unrestricted or were high‐protein (>25% TEI). The types of dietary CHO, fat and protein recommended were predominantly whole foods. Common delivery methods reported were dietician and/or physician involvement, moderate to high frequency of contact (≥1 session/month) and use of participant self‐monitoring. Conclusions Multiple approaches for developing and delivering a low‐CHO diet intervention for T2D management are safe and effective. A comprehensive set of core dietary components to consider in the formulation of low‐CHO diet protocols were identified for use in clinical practice and to inform evidence‐based guidelines for T2D management.

Fat, Sugar or Gut Microbiota in Reducing Cardiometabolic Risk: Does Diet Type Really Matter?

“…There are many studies, meta-analyses, and systematic reviews regarding LCDs' efficiency in T2DM patients [73,77,80,[128][129][130][131][132][133]. A meta-analysis carried out by Turton et al concluded that LCD intervention for T2DM management is safe and effective [128], and one prospective Japanese study showed that LCDs were associated with decreased risk of T2DM in women [129]. A meta-analysis cited in the ECS/EASD guidelines from 2019 [123] indicates that the glucose-lowering effect of low-and high-carbohydrate diets is similar after 1 year or more and there is no significant effect on the weight or LDL-C levels [134].…”

Effects of a low-carbohydrate diet in adults with type 1 diabetes: an interventional study protocol

“…The dietary prescription is based on previously reported approaches shown to be safe and effective in multiple studies of LC diet interventions conducted in individuals with T2D. 9 This study will investigate a LC diet with an adaptive carbohydrate prescription that starts at 50 g of digestible carbohydrate per day and is then adapted (increased or decreased) within a broader range of 25-75 g/day according to individual blood glucose levels and personal preference. Participants will also be encouraged to distribute carbohydrates evenly across the day such that total carbohydrates do not exceed 20 grams at a single eating occasion.…”

“…6,7 Lowcarbohydrate (LC) diets are not clearly defined in the scientific literature but in a recent systematic review (conducted by members of this team), which is the largest systematic review of all LC diets for T2D management available to-date (n=41; including all interventional study designs), LC diet interventions were defined as diets containing ≤130 g/day or 26% TEI from carbohydrate. 9 One 2-year trial (conducted by members of this team) compared a LC diet (14% TEI as carbohydrate) with a traditional HC diet (53% TEI as carbohydrate) in individuals with T2D and achieved greater reductions in diurnal glycaemic variability and diabetes medications alongside improvements in multiple CVD risk markers. 10 This cumulative evidence has led to recent updates in clinical practice guidelines globally, with acceptance of LC diets as an effective therapeutic option for T2D management by national organisations, including diabetes Australia, diabetes UK and the American diabetes association.…”

Effectiveness of a Diabetes Education Program based on Tailored interventions and Theory of Planned Behaviour: Cluster randomized controlled trial protocol

“…Diverse educational models have focused on encouraging patients with T2DM to modify their lifestyles. Some studies have emphasised the need to consume a healthy diet, such as one compatible with the Mediterranean pattern and to moderate the consumption of carbohydrates and/or fats (Turton et al, 2019).…”

“…Diverse educational models have focused on encouraging patients with T2DM to modify their lifestyles. Some studies have emphasised the need to consume a healthy diet, such as one compatible with the Mediterranean pattern and to moderate the consumption of carbohydrates and/or fats (Turton et al., 2019). Others have focused on promoting components associated with physical activity, such as strength, endurance, or aerobic capacity (Huang et al., 2016; Redmon et al., 2010).…”