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Low-carbohydrate diets and type 2 diabetes treatment: a meta-analysis of randomized controlled trials



To assess whether LC diets are associated with long-term improvement in glycemic control and weight loss in people with T2DM, and their cardiovascular and renal safety.


Meta-analysis of randomized controlled trials lasting more than 3 months, retrieved through extensive search on PubMed, Embase,, Cochrane databases up to March 1st, comparing LC diets and balanced carbohydrate diets in people with T2DM.


We retrieved 37 trials, including 3301 patients. Average carbohydrate intake in LC diets was 36% of total energy. LC diets were associated with significant reduction of HbA1c at 3 months (MD − 0.17%, 95% CI − 0.27, − 0.07), no difference at 6 and 12 months, and significant increase at 24 months (MD 0.23%, 95% CI MD 0.02, 0.44). VLC diets were associated with significant HbA1c reduction at 3 and 6 months (MD − 0.43% − 0.60, − 0.26%, and MD − 0.40% 95% CI − 0.59, − 0.22, respectively), but not at 12 and 24 months. LC diets were associated with significant BMI reduction at 6 months (− 1.35 kg/m2 95% CI, − 2.18, − 0.52), but not at other time points. Only a minority of trials reported data on renal function, so renal safety could not be assessed. No significant differences in body weight, lipid profile, or blood pressure were found in the long term.


LC diets may produce small short-term improvements in HbA1c and weight, which are not maintained in the long term. Data on their renal safety are insufficient.

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This research was performed as a part of the institutional activity of the unit, with no specific funding. The manuscript was drafted and revised by the authors in accordance with ICJME standards for authorship. The corresponding author had full access to all the data in the study and had final responsibility for the decision to submit for publication.

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GAS and EM were involved in each of the following points: 1. Design. 2. Data Collection. 3. Analysis. 4. Writing manuscript; LB, VG, and MM were involved in each of the following points: 1. Data Collection. 2. Manuscript revision; FS and ID were involved in each of the following points: 1. Design. 2. Manuscript revision. All the authors approved the final version of this manuscript. Dr. Giovanni Antonio Silverii is the person who takes full responsibility for the work as a whole, including the study design, access to data, and the decision to submit and publish the manuscript.

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Correspondence to G. A. Silverii.

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Conflict of interest

GAS and ID have received speaking fees from Astra Zeneca, Novonordisk; LB, VG, and FG have no conflict of interest; MM has received speaking fees from Astra Zeneca, Bristol Myers Squibb, Boehringer-Ingelheim, Eli-Lilly, Merck, Novo Nordisk, Sanofi, and Novartis and research grants from Bristol Myers Squibb; EM has received consultancy fees from Merck and Novartis speaking fees from Astra Zeneca, Bristol Myers Squibb, Boehringer-Ingelheim, Eli-Lilly, Merck, Novo Nordisk, Sanofi, and Novartis and research grants from Merck, Novartis, and Takeda.

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This article does not contain any studies with human participants or animals performed by any of the authors.

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The present study is a meta-analysis, therefore Informed consent is not required.

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Silverii, G.A., Botarelli, L., Dicembrini, I. et al. Low-carbohydrate diets and type 2 diabetes treatment: a meta-analysis of randomized controlled trials. Acta Diabetol 57, 1375–1382 (2020).

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  • Meta-analysis
  • Type 2 diabetes mellitus
  • Low-carbohydrate diets