Background and aims

The effects of a low carbohydrate/high fat (LCHF) diet on health are debated. This study aims to explore the effects of a diet with less than 20 g carbohydrates per day (LCHF) on plasma low density lipoprotein cholesterol (LDL-C) in young and healthy adults. The secondary aim is the assessment of lipid profile and peripheral blood mononuclear cells (PBMC) gene expression.

Methods

This was a randomized controlled parallel-designed intervention study. Participants were either assigned to a three-week LCHF diet or a control group continuing habitual diet ad libitum, in both groups.

Results

In total, 30 healthy normal weight participants completed the study. Nine subjects did not complete it due to adverse events or withdrawn consent. In the LCHF diet group (n = 15), plasma LDL-C increased from (mean ± SD) 2.2 ± 0.4 mmol/l before intervention to 3.1 ± 0.8 after, while in the control group (n = 15), LDL-C remained unchanged: 2.5 ± 0.8 mmol/l ( p < 0.001 between groups). There was a significant increase in apolipoprotein B, total cholesterol, high-density lipoprotein cholesterol, free fatty acids, uric acid and urea in the LCHF group versus controls. Plasma levels of triglycerides, lipoprotein (a), glucose, C-peptide or C-reactive protein (CRP), blood pressure, body weight or body composition did not differ between the groups. PBMC gene expression of sterol regulator element binding protein 1 (SREBP-1) was increased in the LCHF group versus controls ( p ≤ 0.01). The individual increase in LDL-C from baseline varied between 5 and 107% in the LCHF group.

Conclusions

An LCHF diet for three weeks increased LDL-C with 44% versus controls. The individual response on LCHF varied profoundly.