Low-carb diets may be a health fad, but they may be just as bad for your heart, new research suggests.
A new study finds that low-carbohydrate diets may also be as bad as the high-carb diet as a risk factor for heart disease.
Low-carbers also tend to be more likely to smoke, drink more alcohol and be overweight, according to the new study.
But low-carber diets are also more likely than high-carrier diets to have low levels of cholesterol.
Low-carbing diets, by contrast, are generally associated with more favorable cardiovascular health, including a lower risk of heart attack and stroke, according the study.
The new findings are a first step toward identifying the underlying factors behind these contrasting findings, according Dr. Joseph J. Nierenberg, a cardiologist at the Mayo Clinic who was not involved in the study and who is also an author on the study published online Monday in the journal Circulation.
In the current study, participants were asked to choose between a low- or high-fat diet that contained either 2 grams of carbohydrates per day or 20 grams of saturated fat per day.
Participants who chose a low carb diet were asked if they had consumed at least one serving of the high fat diet and were asked whether they had ever smoked, drank more alcohol, had a BMI of 25 to 29.9 and were overweight.
Participants in the low-fat group were asked about their alcohol consumption.
Those in the high carb group were instructed to eat a low fat diet, but to avoid high-glycemic foods, such as sugary snacks.
The researchers then calculated how many grams of carbohydrate and saturated fat a low or high carb diet provided compared to a high- or low-glycecemic diet.
Participants in the lower-carb group also were asked how often they had smoked, drunk more alcohol or been overweight.
Those in the higher-carb groups were asked questions about their smoking habits, drinking and obesity, including whether they smoked cigarettes, cigars or pipes.
High-carriers were more likely, but not by much, to have used sugary foods, including sugary beverages, as a source of carbohydrates.
High saturated fat diets were associated with a lower prevalence of obesity and heart disease, the researchers found.
The authors wrote that the higher risk of obesity associated with the higher saturated fat intake “was associated with high-density lipoprotein cholesterol (HDL-C) levels of more than 2,000 mg/dL.
High-carb-eating individuals had more LDL-C levels than high carb-eating subjects at baseline, suggesting that these high-saturated fat diets may promote an atherogenic state.”
The researchers noted that the current findings do not prove that the low carb diets were the cause of heart disease in the current population, but rather that low carb intake may be more strongly associated with heart disease risk.
High glycemic index foods were also associated with higher rates of obesity, cardiovascular disease and heart attacks, but were not associated with diabetes, high cholesterol or high blood pressure.
The findings support the hypothesis that the high glycemic-index diet, particularly high-fructose corn syrup, may promote metabolic disorders, including insulin resistance, the authors wrote.
Low carb diets may help to decrease blood sugar, but may also increase insulin resistance and diabetes, the study found.
Low carb diets are a safe way to maintain a healthy weight, and people can reduce their risk of cardiovascular disease with a healthy diet.
The National Institutes of Health supported the study with grants from the National Institutes on Aging, the National Heart, Lung, and Blood Institute, the Walter and Eliza Hall Charitable Trust and the U.S. Department of Agriculture.