National Harbor, Md. (July 27, 2026) — Can a low-carb diet cause your cholesterol to skyrocket? This question has vexed researchers and influencers alike as the popularity of low-carbohydrate diets has surged, yet the evidence has remained mixed. New research suggests that the answer depends on your genes.
According to the study, the high saturated fat intake that tends to accompany a low-carb diet interacts with genetic factors in ways that can increase low-density lipoprotein (LDL) cholesterol, considered a key driver of heart disease risk. The role of genes explains why different individuals can follow the same diet but see different outcomes.
“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 will present the findings at NUTRITION 2026 , the flagship annual meeting of the American Society for Nutrition, held July 25–28 in National Harbor, Maryland, just outside Washington, D.C.
“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.
Previous studies have shown healthy low-carbohydrate diets can support weight loss and blood sugar control for some people, but these diets have inconsistent effects on LDL cholesterol. Researchers sought to find a way to predict who would likely benefit from a low-carb diet and who may see a dangerous spike in LDL cholesterol.
The research is based on data from DIETFITS, a randomized controlled trial in which over 600 adults followed either a healthy low-carb or healthy low-fat diet for a year. The primary study found that neither diet was superior to the other in terms of weight loss. For the new analysis, researchers assessed the relationships among genotype, saturated fat intake, diet type and change in LDL cholesterol from baseline to 6 months in 431 DIETFITS participants with available genetic data.
Among participants following the low-carb diet, the results showed that those with a genetic predisposition toward elevated LDL cholesterol were more likely to see their cholesterol rise. The results also showed that this was driven by a greater sensitivity to saturated fat, meaning that people at higher genetic risk had the largest increases in LDL cholesterol when they consumed more saturated fat. People following a low-fat diet did not show the same patterns.
Unlike prior studies, which have mostly focused on single genetic variants, researchers combined thousands of genetic variants across the genome (creating what is known as a polygenic score) to estimate each participant’s overall tendency for higher or lower LDL cholesterol. In the future, Barad said clinicians could potentially use polygenic scores to help identify people who are more likely to experience adverse LDL cholesterol responses to certain dietary modifications.
However, even without genetic testing, the study offers an important lesson that the response to diet can vary from person to person, underscoring the need to monitor how your body is responding to a dietary change rather than assuming the results will be the same for everyone, Barad added.
Further studies could help to confirm the findings and ensure they apply broadly to diverse populations. General dietary guidance suggests limiting saturated fat to less than 10% of daily calories and favoring unsaturated fats. For those choosing a low-carbohydrate diet, emphasizing healthier fat sources such as nuts, seeds, olive oil and avocado over foods high in saturated fat such as butter, beef tallow, fatty cuts of meat and processed meats may help reduce the risk of adverse cholesterol responses, Barad noted.
Barad will present this research at 2:42 – 2:54 p.m. EDT on Monday, July 27, during the Dietary Composition and Cardiometabolic Outcomes: Mechanistic Insights from Randomized Controlled Trials Oral Session in the Gaylord National Resort & Convention Center ( abstract ; presentation details ).
The DIETFITS trial was funded by grant 1R01DK091831 from the National Institute of Diabetes and Digestive and Kidney Diseases; grants 1K12GM088033 and T32HL007034 from the National Heart, Lung, and Blood Institute; and the Stanford Clinical and Translational Science Award, grant UL1TR001085 from the National Institutes of Health. Dr. Alexa Barad was supported by the American Heart Association Postdoctoral Fellowship (26POST1542318). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or other funders.
Please note that abstracts presented at NUTRITION 2026 were evaluated and selected by a committee of experts but have not generally undergone the same peer review process required for publication in a scientific journal. As such, the findings presented should be considered preliminary until a peer-reviewed publication is available.
About NUTRITION 2026
NUTRITION 2026 is the flagship meeting of the American Society for Nutrition and the premier educational event for nutritional professionals around the globe. NUTRITION brings together lab scientists, practicing clinicians, population health researchers and community intervention investigators to identify solutions to today’s greatest nutrition challenges. The meeting also attracts rising leaders in the field, including undergraduate, graduate, and medical students. NUTRITION 2026 will be held July 25–28 in Washington, D.C. https://nutrition.org/meeting #Nutrition2026
About the American Society for Nutrition (ASN)
ASN is the preeminent professional organization for nutrition research scientists and clinicians around the world. Founded in 1928, the society brings together the top nutrition researchers, medical practitioners, policy makers, and industry leaders to advance knowledge and application of nutrition. ASN publishes four peer-reviewed journals and provides education and professional development opportunities to advance nutrition research, practice, and education. Since 2018, the American Society for Nutrition has presented NUTRITION, the leading global annual meeting for nutrition professionals. http://www.nutrition.org
Find more news briefs from NUTRITION 2026 at: https://www.eurekalert.org/newsroom/nutrition2026 .
###