JACC. AdvancesJul 31, 2024

Links Between a Low-Carb High-Fat Diet, Blood Fats, and Heart Disease Risk

Circadian Biology Weekly Brief ↗PubMed ↗DOI ↗

Updated Apr 6, 2026

Abstract

Consumption of a low-carbohydrate high-fat diet is associated with a significant increase in LDL-C levels and a higher risk of major adverse cardiovascular events.

In a cohort of 2034 individuals on a low-carbohydrate high-fat diet, LDL-C levels were significantly higher compared to 8136 individuals on a standard diet.
11.1% of participants on the low-carbohydrate high-fat diet experienced severe hypercholesterolemia, compared to 6.2% of those on a standard diet.
After an average follow-up of 11.8 years, 9.8% of those on a low-carbohydrate high-fat diet experienced a major adverse cardiovascular event, compared to 4.3% of the standard diet group.
The increased risk of major adverse cardiovascular events remained significant after adjusting for cardiovascular risk factors, with a hazard ratio of 2.18.
Individuals with a higher polygenic risk score for LDL-C showed the most pronounced increases in LDL-C levels on a low-carbohydrate high-fat diet.

Simplified

BACKGROUND: Low-carbohydrate high-fat (LCHF) diets have attracted interest for a variety of conditions. In some individuals, these diets trigger hypercholesterolemia. There are limited data on their effects on cardiovascular disease risk.

OBJECTIVES: The purpose of this study was to investigate the association between LCHF dietary patterns, lipid levels, and incident major adverse cardiovascular events (MACE).

METHODS: In a cohort from the UK Biobank, participants with ≥1 24-hour dietary questionnaire were identified. A LCHF diet was defined as <100 g/day and/or <25% total daily energy from carbohydrates/day and >45% total daily energy from fat, with participants on a standard diet (SD) not meeting these criteria. Each LCHF case was age- and sex-matched 1:4 to SD individuals.

RESULTS: Of the 2034 LCHF and 8136 SD identified participants, 305 LCHF and 1220 SD individuals completed an enrollment assessment concurrently with lipid collection. In this cohort, low-density lipoprotein-cholesterol (LDL-C) and apolipoprotein B levels were significantly increased in the LCHF vs SD group ( < 0.001). 11.1% of LCHF and 6.2% of SD individuals demonstrated severe hypercholesterolemia (LDL-C >5 mmol/L, < 0.001). After 11.8 years, 9.8% of LCHF vs 4.3% of SD participants experienced a MACE ( < 0.001). This difference remained significant after adjustment for cardiovascular risk factors (HR: 2.18, 95% CI: 1.39-3.43, < 0.001). Individuals with an elevated LDL-C polygenic risk score had the highest concentrations of LDL-C on a LCHF diet. Similar significant changes in lipid levels and MACE associations were confirmed in the entire cohort and in ≥2 dietary surveys. P P P P

CONCLUSIONS: Consumption of a LCHF diet was associated with increased LDL-C and apolipoprotein B levels, and an increased risk of incident MACE.

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Competing interests

Dr Brunham has served on advisory boards for Amgen, Novartis, HLS Therapeutics, and Ultragenyx. Dr Iatan has served on advisory boards for Novartis and HLS Therapeutics and receiving honoraria from Novartis and Sanofi. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

PubMed

Links Between a Low-Carb High-Fat Diet, Blood Fats, and Heart Disease Risk

Abstract

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Competing interests

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