Time in range during caloric restriction in type 2 diabetes with obesity

Top Things to Know

Calorie-controlled meal interventions can rapidly improve glycemic outcomes.

Weight loss through nutrition is a key mechanism for metabolic improvement.

Food-based interventions are most effective when they support both weight loss (insulin sensitivity) and preservation of pancreatic function.

Summary of Conclusion/Findings

This 12‑week single-arm intervention study evaluated the effects of caloric restriction on glycemic control in adults with type 2 diabetes and obesity using continuous glucose monitoring (CGM). Participants followed a structured program consisting of 6 weeks of very low-calorie, dietitian-designed meals followed by 6 weeks of a self-managed reduced-calorie diet, resulting in significant improvements in glycemic metrics. Time in range (TIR) increased from 84.3% to 90.3% (P=0.041), alongside reductions in hyperglycemia (time above range) and glycemic variability. Substantial weight loss (BMI reduction from ~29.3 to 26.7 kg/m², P<0.001) was accompanied by marked improvements in insulin sensitivity, which was identified as the primary driver of improved glycemic control. Although early-phase insulin secretion showed only transient improvement, it remained a key determinant of TIR, with stronger glycemic benefits observed in individuals who also had higher insulin sensitivity. Overall, the findings demonstrate that calorie-restricted dietary interventions can significantly improve short-term glycemic control and metabolic function, even in the absence of glucose-lowering medications.