Diet has the potential to be a powerful and cost-effective tool for treatment of type 2 diabetes mellitus (T2D). High-protein diets have shown promise for this purpose. The objective of this systematic review was to evaluate whether high-protein diets improve glycemic outcomes in people with T2D. We conducted a systematic search of literature published prior to 1 February 2018 to find clinical studies of high-protein diet patterns for treatment of T2D in human participants. A high-protein diet was defined as a diet with protein content greater than that of a typical diet in the United States (>16% of total energy as protein). Studies were excluded if weight loss >5% occurred or if no glycemic outcomes were measured. A total of 21 independent articles met our criteria and were included. Most tested diets had a protein content of around 30% of total energy. Many studies supported the use of high-protein diets for patients with T2D, but were limited by small size (n = 8-32) and short duration (1-24 wk). Randomized controlled trials tended to be larger (n = 12-419) and longer (6 wk-2 y), and had mixed results, with many trials showing no difference between a high-protein diet and control. Many randomized controlled trials were limited by low compliance and high dropout rates >15%. There were no consistent beneficial or detrimental effects of high-protein diets on renal or cardiovascular outcomes. Evidence was insufficient to recommend 1 type of protein (plant or animal) over the other. Our review suggests that interventions to improve compliance with diet change over the long term may be equally important as specific macronutrient recommendations for treatment of T2D.
Bibliographical noteFunding Information:
Supported by the National Institutes of Health’s National Center for Advancing Translational Sciences, grants KL2TR002492 and UL1TR002494, and National Institute of Diabetes and Digestive and Kidney Diseases grant T32DK007203. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health’s National Center for Advancing Translational Sciences or National Institute of Diabetes and Digestive and Kidney Diseases. Author disclosures: SM, CB, LSC, and AEB, no conflicts of interest. Supplementary Data are available from the “Supplementary data”link in the online posting of the article and from the same link in the online table of contents at https://academic.oup.com/advances/. SM and CB are co-first authors. Address correspondence to AEB (e-mail: firstname.lastname@example.org). Abbreviations used: BP, blood pressure; FPG, fasting plasma glucose; GFR, glomerular filtration rate; HbA1c, hemoglobin A1c; LoBAG, Low Biologically Available Glucose; PPG, postprandial plasma glucose; TC, total cholesterol; T2D, type 2 diabetes mellitus.
© 2019 American Society for Nutrition.
- diet therapy
- medical nutrition therapy
- type 2 diabetes mellitus
PubMed: MeSH publication types
- Journal Article
- Research Support, N.I.H., Extramural
- Systematic Review