Effects of nutrition therapy on HbA1c and cardiovascular disease risk factors in overweight and obese patients with type 2 diabetes

BACKGROUND: Nutrition Therapy (NT) is essential in type 2 diabetes (T2D) management. Standards of care recommend that each patient engages with a nutritionist (RDN) to develop an individualized eating plan. However, it is unclear if it is the most efficient method of NT. This study evaluates the effects of three different methods of NT on HbA1c and cardiovascular disease risk factors in overweight and obese patients with T2D. METHODS: We randomized 108 overweight and obese patients with T2D (46 M/62F; age 60 ± 10 years; HbA1c 8.07 ± 1.05%; weight 101.4 ± 21.1 kg and BMI 35.2 ± 7.7 kg/m(2)) into three groups. Group A met with RDN to develop an individualized eating plan. Group B met with RDN and followed a structured meal plan. Group C did similar to group B and received weekly phone support by RDN. RESULTS: After 16 weeks, all three groups had a significant reduction of their energy intake compared to baseline. HbA1c did not change from baseline in group A, but decreased significantly in groups B (− 0.66%, 95% CI -1.03 to − 0.30) and C (− 0.61%, 95% CI -1.0 to − 0.23) (p value for difference among groups over time < 0.001). Groups B and C also had significant reductions in body weight, body fat percentage and waist circumference. CONCLUSION: Structured NT alone improves glycemia in comparison to individualized eating plans in overweight and obese patients with T2D. It also reduces other important cardiovascular disease risk factors like body fat percentage and waist circumference. TRIAL REGISTRATION: The trial was retrospectively registered at clinicaltrials.gov(NCT02520050).