Low-carb diets have become increasingly popular, but their effects on cholesterol are far from uniform. Some people see little change, while others experience a substantial increase. New research suggests that genetics may help explain why.
The findings indicate that saturated fat, which can make up a larger share of some low-carb diets, may interact with a person's genetic makeup to raise low-density lipoprotein (LDL) cholesterol, a major contributor to heart disease risk. This genetic influence could help explain why two people following similar diets can have very different cholesterol responses. "Our findings suggest that some individuals may be more sensitive to the LDL cholesterol-raising effects of saturated fat, particularly in the context of a low-carbohydrate diet, because of their genetic background," said Alexa Barad, PhD, RDN, a postdoctoral scholar at Stanford University School of Medicine.
Barad presented the findings at NUTRITION 2026, the flagship annual meeting of the American Society for Nutrition. "These findings highlight that there is real heterogeneity in how people respond to diet. Dietary conversations can sometimes become overly simplified.
One person may say, 'Low-carb diets always raise LDL cholesterol,' while another says, 'My LDL cholesterol did not change at all.' Our findings suggest that both experiences can be true, depending, at least in part, on the individual's genetic makeup," said Barad. Why Low Carb Diets Affect People Differently Earlier research has found that healthy low carbohydrate diets can help some people lose weight and improve blood sugar control. Their impact on LDL cholesterol, however, has been inconsistent.
The researchers wanted to determine whether genetic information could help identify people who are more likely to benefit from eating fewer carbohydrates and those who may instead experience a potentially dangerous rise in LDL cholesterol. The analysis used data from DIETFITS, a randomized controlled trial involving more than 600 adults who followed either a healthy low-carb diet or a healthy low-fat diet for one year. The original trial found no significant advantage for either diet when it came to weight loss.
For the new analysis, the researchers focused on 431 DIETFITS participants for whom genetic data were available. They examined how genotype, saturated fat consumption, diet type, and changes in LDL cholesterol from baseline to 6 months were related. Genetics and Saturated Fat Linked to LDL Increases Among participants assigned to the low-carb diet, those who were genetically predisposed to higher LDL cholesterol were more likely to experience an increase.
Extract — continue reading at the source.
