This was true regardless of an individual’s calorie intake, in the randomized controlled trial published in the Annals of Internal Medicine.
Patients with T2D who ate a low-carb, high-fat diet (LCHF) lost more weight and saw greater improvements in both glycemic control and insulin resistance than those who ate a high-carb, low-fat diet (HCLF), reported lead author Camilla Dalby Hansen, MD, of University of Southern Denmark, Odense, and colleagues, suggesting that this is an effective, nonpharmaceutical treatment option for T2D.
The trial enrolled 185 patients with T2D, for whom low-calorie diets are often recommended to induce weight loss and improve glycemic control.
The trouble with this common recommendation, the investigators wrote, is that it induces hunger, so few patients stick to it.
“Therefore, calorie-unrestricted diets may be a better alternative to achieve long-term maintenance,” Dr. Hansen and colleagues wrote, noting that this approach “is not widely investigated.”
Study methods and results
In the new study, participants were randomized in a 2:1 ratio to follow the LCHF or HCLF diet for 6 months, with no restriction on calorie intake. Patients were evaluated at baseline, 3 months, 6 months, and 9 months (3 months after discontinuation). Parameters included glycemic control, serum lipid levels, and metabolic markers. The final analysis included 165 patients.
While patients in both groups lost weight, those in the LCHF group lost, on average, about 8 pounds more than the HCLF group, a significant difference. While the LCHF diet was associated with greater improvements in glycemic control (HbA1c) than the HCLF diet, it also led to slightly greater increases in LDL levels. In both groups, HDL levels increased, and triglycerides decreased, without significant differences between groups.
The above changes were not sustained 3 months after finishing the diet.
“I believe we have sufficient data to include LCHF as one of the diet options for people with type 2 diabetes,” Dr. Hansen said in a written comment, considering all available data.
Although the diet did lead to significant clinical benefits, she predicted that some patients would still struggle with adherence in the real world.
“The LCHF diet can be difficult for some people to follow,” Dr. Hansen said. “It is a bit more expensive, and it can be difficult to comply to in social gatherings, simply because our society is not suited for this type of diet.”
The magic of unrestricted calories
Jay H. Shubrook, DO, diabetologist and professor at Touro University of California, Vallejo, offered a similar view.
“When you start to fiddle with the diet, it affects not only the person, but all the people they eat with, because eating is a communal experience,” Dr. Shubrook said, in an interview.
Still, he said the present study is “a big deal,” because T2D is a “noncommunicable pandemic,” and “anything we could do that disrupts this process is very important.”
While some may struggle to follow the LCHF diet, Dr. Shubrook predicted better long-term adherence than the low-calorie diet usually recommended.
“What’s magic about this study is because it wasn’t calorie restricted, I think it made it a little bit more flexible for people to continue,” Dr. Shubrook said.
He added that he thinks patients will need a fair amount of coaching and education about food choices in order to lose weight on a diet without calorie restrictions.