Low-carb Diet Could Reduce Risk of These Diseases

People with a condition which raises the risk of type 2 diabetes, heart disease and stroke reversed their symptoms after eating a low-carb diet, according to the authors of a small study.

Scientists at The Ohio State University studied 16 obese people with metabolic syndrome, to see what affect a low-carb diet would have on their health, even if they didn't lose weight.

The term metabolic syndrome describes a group of factors which raises a person's risk of developing conditions including type 2 diabetes, heart disease and stroke. According to the National Heart, Lung and Blood Institute, these factors include a large waistline or an apple-shaped body; a high triglyceride level; low levels of "good" HDL cholesterol; high blood pressure; and high fasting blood sugar.

In the U.S. around a third of adults have metabolic syndrome, and in the past three decades there has been a spike in the amount of carbohydrates people consume, as well as diets linked to obesity in countries around the world, the authors of the study published in the Journal of Clinical Investigation said.

Past studies have shown the health of people with metabolic syndrome improves when they adopt a low-carb diet. However, the authors said this may be because the participants lost weight. They wanted to investigate whether people would reap health benefits if they changed their diet but stayed the same weight. The researchers also set out to test the theory that being unable to process carbohydrates might be a fundamental feature of metabolic syndrome, rather than being obese.

Over a period of four months, the participants—who had an average body fat percentage of 40.2 percent—were assigned high, moderate, and low-carb diets with two-week breaks in between, in a random order. To make sure they didn't lose weight, the researchers gave the participants prepared meals.

Jeff Volek, a professor of human sciences at Ohio State, told Newsweek: "The study took about three years to complete. One of the most challenging aspects was feeding obese individuals enough calories to maintain weight. For some of the larger men, we were providing close to 4,000 kcal/day to maintain their weight."

The diets on average contained 2,950 calories, with 420 grams of carbohydrates in the high carb diet per day; 234 in medium; and 45 in the low. Compared to the high-carb diet, the low-carb diet contained 2.5 times more saturated fat.

"For the low-carbohydrate diet arm, that meant they were eating a lot of fat," Volek told Newsweek. "Nevertheless there were robust improvements in many of the markers of metabolic syndrome. This not only highlights the importance of restricting dietary carbohydrates, but also points to concerns about high-fat being harmful as having no merit."

After following the low-carb diet, the participants saw their triglycerides levels drop and their cholesterol levels improve. Blood sugar levels also got better, and the participants were more efficient at burning fat. However, measures of blood pressure and insulin resistance didn't change.

Of the total, three participants saw their metabolic syndrome reverse after following the moderate carb diet. One person shook off the syndrome after eating high-carb.

Volek said in a statement this might be because the high-carb diet may have still led to a reduction in the carbs consumed normally by the participants.

Despite the high fat content, the low-carb diet resulted in lower levels of saturated fat in the bloodstream. It also seemed to increase the size of cholesterol particles in the blood, which is associated with a lower risk of cardiovascular disease.

"There's no doubt that people with metabolic syndrome and type 2 diabetes do better on low-carb diets, but they typically lose weight and one of the prevailing thoughts is that the weight loss is driving the improvements. That was clearly not the case here," Volek said in a statement.

"Our view is that restricting carbs even without weight loss improves a host of metabolic problems. Obviously, quality of diet matters because quantity is locked down in this experiment. Even a modest restriction is carbs is enough to reverse metabolic syndrome in some people, but others need to restrict even more," he said.

Volek predicts that if the participants had lost weight, more would have seen their metabolic syndrome disappear.

In a separate study looking at diet and health published last week, scientists found a link between eating red meat and a higher risk of death. The authors of the work published in the journal BMJ believe cutting down on foods like burgers and bacon could lead to a longer life.