A Ketogenic Low-Carbohydrate High-Fat Diet Increases LDL Cholesterol in Healthy, Young, Normal-Weight Women: A Randomized Controlled Feeding Trial

Abstract

Ketogenic low-carbohydrate high-fat (LCHF) diets are popular among young, healthy, normal-weight individuals for various reasons. We aimed to investigate the effect of a ketogenic LCHF diet on low-density lipoprotein (LDL) cholesterol (primary outcome), LDL cholesterol subfractions and conventional cardiovascular risk factors in the blood of healthy, young, and normal-weight women. The study was a randomized, controlled, feeding trial with crossover design. Twenty-four women were assigned to a 4 week ketogenic LCHF diet (4% carbohydrates; 77% fat; 19% protein) followed by a 4 week National Food Agency recommended control diet (44% carbohydrates; 33% fat; 19% protein), or the reverse sequence due to the crossover design. Treatment periods were separated by a 15 week washout period. Seventeen women completed the study and treatment effects were evaluated using mixed models. The LCHF diet increased LDL cholesterol in every woman with a treatment effect of 1.82 mM (p < 0.001). In addition, Apolipoprotein B-100 (ApoB), small, dense LDL cholesterol as well as large, buoyant LDL cholesterol increased (p < 0.001, p < 0.01, and p < 0.001, respectively). The data suggest that feeding healthy, young, normal-weight women a ketogenic LCHF diet induces a deleterious blood lipid profile. The elevated LDL cholesterol should be a cause for concern in young, healthy, normal-weight women following this kind of LCHF diet.

The effects of fat consumption on low-density lipoprotein particle size in healthy individuals: a narrative review

“…Nonmeat diet: 34% E fat (7% E SFA, 20% E MUFA, 5% E PUFA), 41% E CHO, 25% E PRO (16% E vegetable protein). ↑LDL-C ↑large LDL particle concentrations (High SFA compared with low SFA, independent of protein source) ↔small- and medium-sized LDL particle concentrations (High SFA intake compared with low SFA intake) Buren et al (2021) [ 100 ] Randomized Crossover PAGGE 17 females 19–27 years median, 23.8 years 23 weeks Each diet was consumed for 4 wk., separated by a 15 wk. washout period.…”

“…In another investigation, the consumption of a ketogenic diet (77% E fat and 4% E CHO) for 4 wk. increased both sdLDL and large, buoyant LDL particles [ 100 ]. There were no significant differences in percentages or concentrations of LDL subclasses in participants following a very-low CHO diet (60% E fat and 10% E CHO) or a low-fat diet (19% E fat and 62% E CHO) for 4 wk.…”

“…The inclusion of diets containing olive oil, sunflower oil, or rapeseed oil produced inconsistent outcomes regarding LDL size, perhaps due to the differing ingredients, such as vitamins and phytochemicals [ 27 , 81 , 85 ]. There were inconsistent results in LDL size after adhering to ketogenic or very-low carbohydrate diets [ 33 , 89 , 100 ]. Lastly, males displayed higher concentrations of sdLDL particles compared to females [ 26 ].…”

Is High Cholesterol Deleterious? An Alternative Point of View. Comment on Burén et al. A Ketogenic Low-Carbohydrate High-Fat Diet Increases LDL Cholesterol in Healthy, Young, Normal-Weight Women: A Randomized Controlled Feeding Trial. Nutrients 2021, 13, 814

“…In their study of the effect of an LCHF-diet on blood lipids, Burén et al became worried because, after a few weeks, the participants' LDL-cholesterol (LDL-C) increased significantly [1]. However, they need not worry.…”

Reply to Ravnskov, U. Is High Cholesterol Deleterious? An Alternative Point of View. Comment on “Burén et al. A Ketogenic Low-Carbohydrate High-Fat Diet Increases LDL Cholesterol in Healthy, Young, Normal-Weight Women: A Randomized Controlled Feeding Trial. Nutrients 2021, 13, 814”

“…We thank Ravnskov [ 1 ] for his interest in our recent publication [ 2 ]. In our study, low-density lipoprotein cholesterol (LDL-C) and Apolipoprotein B-100 (ApoB) almost doubled in young, healthy women when they followed the ketogenic low-carbohydrate high-fat (LCHF) diet.…”