Your Low-Carb Diet Might Be Raising Your Cholesterol – But It Depends On Your Genes
Lots of people hear that a diet worked for their friend and and assume it will work for them too. But when they test it out, they're sorely disappointed to see completely different results.
This assumption is especially true with low-carb eating and when it comes to your cholesterol. For some people a low-carb diet is super helpful for cholesterol management, while for others it sends LDL soaring. A new study from the Stanford School Of Medicine suggest this has less to do with the diet itself and more to do with your DNA.
What the research found
LDL cholesterol is considered a key driver of heart disease risk, which makes it an important number to keep track of as you age. New research presented at NUTRITION 2026, the annual meeting of the American Society for Nutrition, found that your genetic makeup impacts how a low-carb diet affects your LDL cholesterol.
The analysis drew on data from DIETFITS, a randomized controlled trial in which more than 600 adults followed either a healthy low-carb or healthy low-fat diet for a year. Researchers focused on 431 participants who had genetic data available, tracking how their LDL cholesterol changed from baseline to six months.
Among those following the low-carb diet, people with a genetic predisposition toward elevated LDL were more likely to see their cholesterol rise. Those at a higher genetic risk showed the greatest increases in LDL when they consumed more saturated fat, a natural byproduct of eating low-carb, since the diet tends to be higher in fat overall. People on the low-fat diet did not show the same pattern.
"There is real heterogeneity in how people respond to diet," says Alexa Barad, Ph.D., RDN, the study's lead researcher, in a press release. She explains that dietary conversations can sometimes become overly simplified. One person may find low-carb diets always raise cholesterol, while another finds it doesn't affect their cholesterol at all. "Our findings suggest that both experiences can be true, depending, at least in part, on the individual's genetic makeup," she says.
Which genes matter here
Rather than looking at a single genetic variant, which what most prior research in this area did, the researchers combined thousands of genetic variants across the genome to create what's called a polygenic score. Think of it as a summary of your overall genetic tendency toward higher or lower LDL cholesterol.
The polygenic score helped explain why some people are more sensitive to saturated fat than others. Those with a higher score, meaning a stronger genetic lean toward elevated LDL, were the ones most affected by the saturated fat that comes with low-carb eating.
The researchers hope clinicians could potentially use polygenic scores in the future to identify people who are more likely to see adverse LDL responses to certain dietary changes, allowing them to better guide nutrition decisions.
What this means if you don't have genetic testing
Most people don't have access to polygenic scores, and that's okay. The bigger takeaway from this research is simpler: your response to a diet is personal.
If you're following a low-carb diet, getting your cholesterol checked before you start, and again a few months in, is a practical way to see how your body is responding. Don't assume your results will mirror someone else's, even if you're eating the same foods.
The fat choices that may make a difference
For those who want to eat low-carb without the cholesterol risk, you have to be extra vigilant about the type of fat you are eating. General dietary guidance recommends limiting saturated fat to less than 10% of daily calories. On a low-carb diet, that means leaning toward unsaturated fat sources like:
- Nuts and seeds: a versatile, portable option that fits easily into low-carb eating
- Olive oil: a staple unsaturated fat for cooking and dressings
- Avocado: rich in monounsaturated fats and easy to add to most meals
You should also be more mindful of saturated fat sources like butter, beef tallow, fatty cuts of meat, and processed meats, especially if you have a family history of high cholesterol or heart disease.
The takeaway
Most people don't have access to polygenic scores, and that's okay. The bigger takeaway from this research is far simpler: your response to a diet is personal. Don't assume your results will mirror someone else's, even if you're eating the same foods.
If you're following a low-carb diet, getting your cholesterol checked before you start, and again a few months in, is a practical way to see how your body is responding. And, no matter what dietary changes you are making, keep track of the effects so you can figure out what works best for you.