Protocol for a randomized controlled trial comparing a very low-carbohydrate diet or moderate-carbohydrate plate-method diet for type 2 diabetes: the LEGEND (Lifestyle Education about Nutrition for Diabetes) trial

Trials. 2023 Jul 20;24(1):463. doi: 10.1186/s13063-023-07512-9.

Abstract

Background: Optimal carbohydrate intake is an important and controversial area in the nutritional management of type 2 diabetes. Some evidence indicates that reducing overall carbohydrate intake with a low- or very low-carbohydrate eating plan can improve glycemic control compared to following eating plans that involve greater carbohydrate intake. However, critical knowledge gaps currently prevent clear recommendations about carbohydrate intake levels.

Methods: The LEGEND (Lifestyle Education about Nutrition for Diabetes) Trial aims to compare a very low-carbohydrate diet to a moderate-carbohydrate plate-method diet for glycemic control in adults with type 2 diabetes. This two-site trial plans to recruit 180 adults with type 2 diabetes. We will randomize participants to either a 20-session group-based diet and lifestyle intervention that teaches either a very low-carbohydrate diet or a moderate-carbohydrate plate-method diet. We will assess participants at study entry and 4 and 12 months later. The primary outcome is HbA1c, and secondary outcomes include inflammation (high sensitivity C-reactive protein), body weight, changes in diabetes medications, lipids (small particle LDL, HDL, triglycerides), skeletal metabolism (bone mineral density from dual-energy x-ray absorptiometry and bone turnover markers serum procollagen type I N propeptide and serum C-terminal telopeptide of type I collagen), and body composition (percent body fat, percent lean body mass).

Discussion: The LEGEND trial is a randomized controlled trial to assess optimal carbohydrate intake in type 2 diabetes by evaluating the effects of a very low-carbohydrate diet vs. a moderate-carbohydrate plate-method diet over a year-long period. The research addresses important gaps in the evidence base for the nutritional management of type 2 diabetes by providing data on potential benefits and adverse effects of different levels of carbohydrate intake.

Trial registration: ClinicalTrials.gov NCT05237128. Registered on February 11, 2022.

Keywords: Glycemic control; Lifestyle intervention; Randomized controlled trial; Type 2 diabetes.

Publication types

  • Clinical Trial Protocol

MeSH terms

  • Adult
  • Blood Glucose / metabolism
  • Carbohydrates
  • Diabetes Mellitus, Type 2*
  • Diet, Carbohydrate-Restricted
  • Humans
  • Life Style
  • Randomized Controlled Trials as Topic

Substances

  • Procollagen Type I
  • Carbohydrates
  • Blood Glucose

Associated data

  • ClinicalTrials.gov/NCT05237128