Discover how genetics affect cholesterol response to low-carb diets. Learn about personalized dietary plans for better heart health.
For years, low-carbohydrate diets have been praised for helping people lose weight, control blood sugar, and even improve some markers of heart health. But they have also sparked a long-running debate: Why do some people see their cholesterol levels improve while others experience a sharp rise in “bad” cholesterol (1✔ ✔Trusted Source
Nutrition 2026. A World-Class Nutrition Science Meeting Right in the DC Area
)?
New research suggests the answer may lie in your genes.
Scientists have found that a person’s genetic makeup can influence how their body responds to the high saturated fat intake that often accompanies a low-carb diet. The findings could pave the way for more personalized nutrition advice, helping people choose diets that match their individual biology rather than relying on one-size-fits-all recommendations.
The study will be presented at NUTRITION 2026, the annual meeting of the American Society for Nutrition.
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Why Low-Carb Diets Affect People Differently
Low-carbohydrate diets reduce foods rich in carbohydrates, such as bread, rice, pasta, and sugary snacks, while increasing proteins and fats. Many people adopt them to lose weight or better manage diabetes.
However, these diets often include higher amounts of saturated fat, found in foods such as butter, fatty cuts of meat, processed meats, and animal fats.
While previous studies have shown that healthy low-carb diets can support weight loss and improve blood sugar control, their effect on low-density lipoprotein (LDL) cholesterol—often called the “bad” cholesterol—has remained inconsistent.
Some people experience little or no change, while others see LDL cholesterol increase substantially. Researchers wanted to understand why.
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Genes May Hold the Answer
The new study suggests that the body’s response to saturated fat is partly determined by genetics.
“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 Dr. Alexa Barad, a postdoctoral scholar and registered dietitian at Stanford University School of Medicine.
She explained that dietary advice often becomes oversimplified.
“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.”
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More Than 600 Adults Took Part in the Study
The findings are based on data from DIETFITS, a randomized clinical trial involving more than 600 adults, who followed either a healthy low-carbohydrate diet or a healthy low-fat diet for one year.
The original trial showed that neither diet was clearly superior for weight loss.
For the new analysis, researchers examined 431 participants whose genetic information was available.
Instead of looking at a single gene, scientists used a polygenic score—a measure that combines thousands of genetic variations across the genome—to estimate each person’s inherited tendency toward higher or lower LDL cholesterol.
Researchers then compared genetic risk, saturated fat intake, diet type, and changes in LDL cholesterol over the first six months.
People with Higher Genetic Risk Saw Larger Cholesterol Increases
Among participants following the low-carbohydrate diet, those with a greater inherited risk of high LDL cholesterol experienced the biggest increases in cholesterol levels.
The researchers found that these individuals appeared to be more sensitive to saturated fat than people with lower genetic risk.
Interestingly, the same pattern was not observed in participants following a low-fat diet, suggesting that the interaction between genes and saturated fat plays a major role in determining cholesterol responses.
The findings may help explain why two people can eat nearly identical diets but experience very different health outcomes.
Personalized Nutrition Could Be the Next Step
The researchers believe genetic testing could eventually become a valuable tool for tailoring dietary advice.
Rather than recommending the same eating plan to everyone, doctors could one day use polygenic scores to predict who is more likely to develop unhealthy cholesterol levels on a low-carb diet.
Such an approach would represent a major step toward precision nutrition, where dietary recommendations are customized according to a person’s genetic profile, lifestyle, and health risks.
Healthy Fat Choices Still Matter
While genetic testing is not yet part of routine dietary counseling, the researchers say the study offers an important practical message.
People should avoid assuming that a popular diet will produce the same results for everyone.
Instead, experts recommend monitoring cholesterol levels after making significant dietary changes and working with healthcare professionals to evaluate individual responses.
Current dietary guidelines continue to recommend limiting saturated fat to less than 10% of daily calories and replacing it with healthier unsaturated fats whenever possible.
For people choosing a low-carbohydrate diet, experts suggest emphasizing foods such as:
- Nuts and seeds
- Olive oil
- Avocados
- Other unsaturated fat sources
At the same time, they recommend limiting foods rich in saturated fat, including butter, beef tallow, processed meats, and fatty cuts of red meat.
More Research Is Needed
The researchers caution that the findings should be confirmed in larger and more diverse populations before genetic testing becomes part of routine nutritional care.
Still, the study reinforces a growing understanding in nutrition science: there is no single “best” diet for everyone.
As researchers continue to uncover how genes influence metabolism, cholesterol, and heart disease risk, personalized nutrition may become an increasingly important part of preventive healthcare.
For now, the message is clear: if you’re considering a low-carb diet, don’t rely solely on online success stories. Monitoring your cholesterol—and recognizing that your genes may shape your response—could be just as important as counting carbohydrates.
Reference:
- Nutrition 2026. A World-Class Nutrition Science Meeting Right in the DC Area – (https://nutrition.org/meeting/)
Source-Medindia