Calorie-restricted diets help patients with type 2 diabetes achieve remission

Key takeaways:

• Calorie-restricted diets, regardless of macronutrient composition, may be effective interventions for type 2 diabetes remission.
• More trials are needed to assess the long-term effects.

Calorie-restricted diets, particularly in conjunction with an intensive lifestyle modification program, were associated with increased remission rates among patients with type 2 diabetes, according to a meta-analysis of 28 randomized trials.

Ahmad Jayedi, MS, a dietitian at Semnan University of Medical Sciences and a PhD candidate at Tehran University of Medical Sciences in Iran, and colleagues wrote in the American Journal of Clinical Nutrition that there is not much evidence on the dose-dependent effects of calorie restriction in patients with type 2 diabetes.

“It is established that improving glycemic control can reduce the risks of microvascular complications and cardiovascular disease events and that diet therapy is a key component in type 2 diabetes management programs,” they wrote. “This has led to recommendations that, with the help of a health care team, people with type 2 diabetes should adopt an individualized healthy eating plan to optimize glycemic control and long-term health. More recently, more intensive caloric restriction and structured lifestyle interventions have been shown to achieve remission from type 2 diabetes.”

However, they wrote, the impact of calorie restriction “has not been comprehensively evaluated.”

To learn more, the researchers conducted a systematic review and meta-analysis of 28 randomized trials that assessed how a pre-specified calorie-restricted diet affected remission of type 2 diabetes. The trials were at least 12 weeks long and included 6,281 participants.

When defining remission as an HbA1c of less than 6.5% without medication, the researchers found that calorie-restricted diets increased remission by 38 (95% CI, 9-67) more per 100 patients at 6 months and by 13 (95% CI, 10-18) more per 100 patients at 12 months compared with usual care.

When defining remission as an HbA1c of less than 6.5% at least 2 months after stopping medication, remission increased by 34 (95% CI, 15-53) more per 100 patients at 6 months and by 16 (95% CI, 4-49) more per 100 patients at 12 months.

The researchers noted that the American Diabetes Association recently recommended that most people with overweight, obesity or type 2 diabetes adopt a lifestyle intervention program that includes weight loss by a 500 to 750 kcal per day energy deficit — about 1,500 to 1,800 kcal per day for men and 1,200 to 1,500 kcal per day for women.

Jayedi and colleagues found, at 6 months, each 500 kcal per day decrease in energy intake resulted in clinically meaningful reductions in HbA1c (mean difference, -0.82%; 95% CI, -1.05 to -0.59) and body weight (mean difference, -6.33 kg; 95% CI, -7.76 to -4.9), which they wrote “attenuated remarkably” at the year mark.

“Current evidence suggests that clinical benefits generally appear after 3-5% weight loss, and the benefits of weight loss are progressive, with more intensive weight loss indicating further health improvements,” they wrote. “Our results presented further supportive evidence, indicating that levels of HbA1c, fasting plasma glucose ... and body weight decreased linearly along with the decrease in energy intake.”

The researchers concluded that more trials are needed to confirm the long-term effects of calorie restriction in type 2 diabetes, as “confusion remains about the degree of calorie restriction to choose in patients with type 2 diabetes for implementing the most effective lifestyle interventions.”