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Meta-Analysis
. 2020 Dec 9;12(12):3774.
doi: 10.3390/nu12123774.

The Effect of Low-Fat and Low-Carbohydrate Diets on Weight Loss and Lipid Levels: A Systematic Review and Meta-Analysis

Shreya Chawla  1 , Fernanda Tessarolo Silva  2 , Sofia Amaral Medeiros  2 , Rania A Mekary  3   4 , Dina Radenkovic  5
Affiliations
Meta-Analysis

The Effect of Low-Fat and Low-Carbohydrate Diets on Weight Loss and Lipid Levels: A Systematic Review and Meta-Analysis

Shreya Chawla et al. Nutrients. .

Abstract

Background: The rise in obesity has emphasised a focus on lifestyle and dietary habits. We aimed to address the debate between low-carbohydrate and low-fat diets and compare their effects on body weight, low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), total cholesterol, and triglycerides in an adult population.

Method: Medline and Web of Science were searched for randomised controlled trials (RCTs) comparing low-fat and low-carbohydrate diets up to September 2019. Three independent reviewers extracted data. Risk of bias was assessed using the Cochrane tool. The meta-analysis was stratified by follow-up time using the random-effects models.

Results: This meta-analysis of 38 studies assessed a total of 6499 adults. At 6-12 months, pooled analyses of mean differences of low-carbohydrate vs. low-fat diets favoured the low-carbohydrate diet for average weight change (mean difference -1.30 kg; 95% CI -2.02 to -0.57), HDL (0.05 mmol/L; 95% CI 0.03 to 0.08), and triglycerides (TG) (-0.10 mmol/L; -0.16 to -0.04), and favoured the low-fat diet for LDL (0.07 mmol/L; 95% CI 0.02 to 0.12) and total cholesterol (0.10 mmol/L; 95% CI 0.02 to 0.18). Conclusion and Relevance: This meta-analysis suggests that low-carbohydrate diets are effective at improving weight loss, HDL and TG lipid profiles. However, this must be balanced with potential consequences of raised LDL and total cholesterol in the long-term.

Keywords: cardiology; cardiovascular outcomes; cholesterol; lipid panel; low carbohydrate diet; low fat diet; nutrition; preventative medicine; weight loss.

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Conflict of interest statement

Dina Radenkovic reports personal fees from Health, Longevity, Performance Optimisation Institute, outside the submitted work. The remaining authors declare no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years, no other relationships or activities that could appear to have influenced the submitted work.

Figures

Figure 1
Figure 1
Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram of included articles.
Figure 2
Figure 2
Forest plots showing weighted mean differences (WMD) and 95% CI across all studies and time periods for weight loss.
Figure 3
Figure 3
Forest plots showing weighted mean differences (WMD) and 95% CI across all studies and time periods for (a) Low-density lipoprotein cholesterol (LDL) cholesterol, (b) High-density lipoprotein cholesterol (HDL) cholesterol, (c) Total cholesterol, (d) Triglycerides.
Figure 4
Figure 4
Quality assessment performed by authors on each risk of bias item presented as percentage across all included studies.
See this image and copyright information in PMC

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