Your Low Carb Diet Won't Kill You, But It's Probably Not a Good Idea

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Could cutting carbs cut your life short? A new, preliminary study suggests that there may be a link between a low-carb diet and an increased risk of early death, but more research is needed before doctors will advise loading up on bread and pasta.

The findings were presented today (Aug. 28) at the European Society of Cardiology Congress in Vienna. The study has not yet been published in a peer-reviewed journal.

In the study, researchers in Poland looked at data on nearly 25,000 Americans who had participated in the U.S. National Health and Nutrition Examination Survey (NHANES) at some pointbetween 1999 and 2010. After a six-year follow-up period, the researchers found that people who reported following a low-carb diet (like the Atkins diet, the keto diet or just a diet that cuts out carbs) had a 32 percent higher risk of death during the follow-up period compared with those who didn't follow a low-carb diet. What's more, people following a low-carb diet were 51 percent more likely to die from heart disease, 50 percent more likely to die from cerebrovascular disease and 35 percent more likely to die from cancer during the follow-up period than people who didn't follow a low-carb diet. [7 Foods Your Heart Will Hate]

Study author Maciej Banach, a researcher at the Medical University of Lodz in Poland, confirmed the results by comparing them to data from other studies.

"The message from our study is clear," Banach told Live Science. "Very long-term [low-carb dieting] should be avoided."

Banach noted several important limitations of the study, however. Because the follow-up period lasted only six years and the NHANES data is self-reported from one point in time, he can't say definitively what counts as "very-long term" or sufficiently low-carb to be dangerous.

Alice Lichtenstein, director of the Cardiovascular Nutrition Laboratory at Tufts University and a nutrition expert who was not involved with the new study, said there are some important holes in this study that lead her to be skeptical of its claims.

For example, people who already had a higher risk of developing heart disease, stroke or hypertension might've been the ones who were more likely to adopt a low-carb diet, Lichtenstein told Live Science, but it's unclear from the data if that was the case.

And, of course, "association does not necessarily prove causation," Lichtenstein said. In other words, it's possible that the people in the study who adopted low-carb diets were already less healthy than the general population. So, the increased rates of heart disease mortality and death among low-carb dieters could have more to do with the dieters themselves than their diets.

Lichtenstein also said she's skeptical that all the people who reported low-carb diets in the study were really adhering to them properly. "We don't know that this was super low-carb, because it was self-reported," she said.

Still, Lichtenstein said that she doesn't recommend low-carb diets for most people, because people don't tend to stick to them.

"You really need to think in the long term rather than the short term," she said. "Any of these diets that are relatively extreme and [that], in some cases, can inhibit people's social interaction — because they start worrying, 'If I go out, will I be tempted?' — the long-term data isn't particularly solid."

A healthy diet for most people, she said, is neither very low-carb nor very low-fat. Instead, it's high in fruits and vegetables, whole grains, fish, and legumes and low in added sugars and saturated fats. And, of course, it's within a healthy calorie limit.

Originally published on Live Science.

Rafi Letzter
Staff Writer
Rafi joined Live Science in 2017. He has a bachelor's degree in journalism from Northwestern University’s Medill School of journalism. You can find his past science reporting at Inverse, Business Insider and Popular Science, and his past photojournalism on the Flash90 wire service and in the pages of The Courier Post of southern New Jersey.