A low-carb diet for 4 weeks reversed metabolic syndrome without weight loss in 50% of the study participants.
The low-carb diet also decreased triglycerides and improved LDL cholesterol metabolism by decreasing small, dense LDL particles.
Small, dense LDL particles are thought to be more atherogenic and have been shown to form in the presence of both saturated fat and refined carbohydrates.
You can read more about the role of small, dense LDL particles in atherosclerosis on the summary of the podcast I did. with Dr. Ronald Karauss (one of the study authors).
Dr. Krauss episode page: https://www.foundmyfitness.com/episodes/ronald-krauss