Two diets with different haemoglobin A1c and antiglycaemic medication effects despite similar weight loss in type 2 diabetes

Abstract

We analyzed participants with type 2 diabetes (n=46) within a larger weight loss trial (n=146) who were randomized to 48 weeks of a low-carbohydrate diet (LCD; n=22) or a low-fat diet + orlistat (LFD+O; n=24). At baseline, mean BMI was 39.5 kg/m2 (SD 6.5) and HbA1c 7.6% (SD 1.3). Although the interventions reduced BMI similarly (LCD −2.4 kg/m2; LFD+O −2.7 kg/m2, p= 0.7), LCD led to a relative improvement in hemoglobin A1c: −0.7% in LCD vs. +0.2% in LFD+O (difference −0.8%, 95% CI= −1.6, −0.02; p=0.045). LCD also led to a greater reduction in antiglycemic medications using a novel medication effect score (MES) based on medication potency and total daily dose; 70.6% of LCD vs. 30.4% LFD+O decreased their MES by ≥50% (p=0.01). Lowering dietary carbohydrate intake demonstrated benefits on glycemic control beyond its weight loss effects, while at the same time lowering antiglycemic medication requirements.

A Very Low-Carbohydrate, Low–Saturated Fat Diet for Type 2 Diabetes Management: A Randomized Trial

“…Previous studies in T2DM show that, compared with an HC diet, an LC diet achieves at least comparable reductions in body weight, blood pressure, and insulin concentrations (6)(7)(8), with greater improvements in glycemic control (6,(8)(9)(10). However, these studies are limited by poor dietary compliance and the absence and/or control of physical activity, an integral component of lifestyle modification for weight and diabetes management (11).…”

A 12-week low-carbohydrate, high-fat diet improves metabolic health outcomes over a control diet in a randomised controlled trial with overweight defence force personnel

“…These outcomes are important because triglyceride:HDLc ratio is becoming increasingly well-recognised and utilised in a clinical setting as a useful predictor of insulin resistance and cardiovascular disease risk factors (McLaughlin et al 2005). While we cannot say for certain as to whether these metabolic improvements have occurred independent of weight loss, evidence suggests that both lipid and glycaemic control markers have shown improvements in the absence of weight loss (Krauss et al 2006;Gannon and Nuttall 2006;Mayer et al 2014). Furthermore, greater improvements in triglyceride and HDLc have been shown in low carbohydrate diets compared with isocaloric low fat diets in the context of equal group weight loss, thereby suggesting an independent impact of macronutrient redistribution (Brinkworth et al 2009).…”

A randomised trial comparing low-fat diets differing in carbohydrate and protein ratio, combined with regular moderate intensity exercise, on glycaemic control, cardiometabolic risk factors, food cravings, cognitive function and psychological wellbeing in adults with type 2 diabetes: Study protocol

“…To compare changes in antihyperglycaemic medication regimes between the 2 groups, a MES was calculated at the end of each phase. This study chose a technique described in a dietary intervention study with a T2DM population [27] as it captures potency, dose changes as well as discontinued medications compared to other methods which only consider the total number of diabetes medications taken [28]. The percentage of the maximum daily dose for each class of medication was calculated and multiplied by the medication's corresponding adjustment factor.…”

“…The MES is the sum of each of these calculations. The maximum daily dose was obtained from the Monthly Index of Medical Specialties (MIMS) Australia [29] with insulin considered to be 1unit/kg/day of baseline weight [27]. The adjustment factor is the mean decrease in HbA1c expected with monotherapy with the following values used: Biguanides …”