Credit: Pixabay.

Diets that focus on consuming as few carbohydrates as possible are popular — they might also be extremely harmful. According to a recent study, individuals who were on a low-carb diet had a greater risk of premature death, particularly due to coronary heart disease, stroke, and cancer. The authors conclude that “these diets should be avoided.”

The study examined the relationship between low carbohydrate diets and all-cause death in a nationally representative sample of 24,825 participants of the US National Health and Nutrition Examination Survey (NHANES) from 1999 to 2010.

The participants were at an average of 47.6 years of age and almost equally represented men and women. The international team of researchers divided them into quartiles based on the proportion of carbohydrates present in their diets. Risks of death from coronary heart disease, cerebrovascular disease, and cancer were increased by 51%, 50%, and 35%, respectively. The link was strongest in non-obese, older participants, researchers reported today at the European Society of Cardiology Congress 2018. 

Carbohydrates include foods such as fruit, vegetables, and sugar, but most often people ingest the most carbs from starchy foods such as potatoes, rice, and pasta. Low-carb diets are touted as being highly effective for weight loss. However, studies such as this suggest that, in the long run, low-carb diets can be dangerous.

Forest plot of low carbohydrate diets and risk of total mortality. Credit: European Society of Cardiology.

But that’s not to say that people should eat a lot of carbs. Finding that sweet spot is challenging work, which Maciej Banach, a Professor at the Medical University of Lodz, Poland, and one of the lead authors of the study, is trying to answer. He and colleagues wanted to answer exactly what level of carbohydrates, expressed in grams, in every-diet might be considered dangerous. They were not able to answer this directly due to the way carb intake is being evaluated nowadays — using the Willett method, which expresses a percentage of energy from a given nutrient.

The authors also plan on investigating when a low-carb diet stops offering dividends and starts to negatively affect health. In the short-term, low-carb dieting not only leads to weight loss but also lowers blood pressure and improves blood glucose control.

“Now we have been working to give direct answer on the number of calories and/or grams of carbohydrates per day that might be acceptable in our diet. But we believe that for carbohydrates it is a kind of U-curve, so for sure we should avoid too much carbohydrates in our diet, but, based on our results, it is also not recommended to use restricted low carbohydrates diet, especially for the long-time,” Banach told ZME Science.

Another study recently, published in The Lancet, which followed 15,428 American adults aged 45-64 years from 1987 until 2012, found that low-carb diets were associated with reduced lifespan. The findings were confirmed by a meta-analysis of data from eight prospective cohorts involving 432,179 people in North American, European, and Asian countries.

“It is usually recommended to use a healthy, well-balanced diet in order to lose weight max. 1 kg per week (usually about 1000 calories per day). There are many well-known and very healthy diets, with great scientific evidence, including Mediterranean or DASH diets,” Banach said.