Blood sugar control is essential for managing type 2 diabetes and reducing the chance of developing its potential long-term complications. Diet is of the utmost importance; however, the ideal diet for a person with diabetes is a subject of debate. A new study compared a low-carb, high-fat diet (LCHF) to a high-carb, low-fat (HCLF) diet to see which one provided better weight loss and blood sugar control.

Over 480 million people globally have type 2 diabetes. In the United States, more than 37 million people live with diabetes, and 90 to 95 percent of them have type 2 diabetes. Uncontrolled type 2 diabetes can lead to complications such as kidney disease, cardiovascular disease, and nerve and vision problems.

People who ate the low carb diet saw the most beneficial changes, including a reduction in their hemoglobin A1C. They also lost about eight pounds more than those following the low-fat diet.

In addition, over half of those with diabetes have nonalcoholic fatty liver disease (NAFLD) which can impair liver function and lead to permanent damage. Studies have shown that weight loss helps control diabetes and NAFLD, and blood sugar control can be improved by restricting carbohydrate intake.

University of Southern Denmark researchers randomly assigned 165 people who had type 2 diabetes to eat either a low-carb, high-fat diet or a high-carb, low-fat diet for six months. Each of the participants ate the same number of calories that they burned each day.

One group ate a low carbohydrate diet with no more than 20 percent of their calories from carbohydrates, 20 to 30 percent from protein and 50 to 60 percent of calories from fat. The other group ate roughly half of their calories as carbohydrate, and the other 50 percent was split equally between fat and protein.

People who ate the low carb diet saw the most beneficial changes, including a 0.59 percent reduction in their hemoglobin A1C. They lost eight pounds more than those following the low-fat diet, more body fat and shrank their waistline. After six months, both groups had higher levels of “good” HDL cholesterol and lower triglycerides.

No difference was observed in the amount of fat in the liver or liver inflammation in either group.

Unfortunately, when the study was over the participants went back to their old eating patterns and so did not sustain any of the positive health improvements they had achieved.

Long-term compliance with diet is key to managing diabetes. There is plenty of evidence that people with type 2 diabetes can often control their blood sugar without taking medication; however, patients have to be dedicated to lifelong diet and lifestyle changes like being active every day and cutting out — or at least cutting back on — sugar-sweetened beverages.

The study is published in Annals of Internal Medicine.