In a recent study published in Nutrition & Diabetes, researchers evaluated the impact of low-carbohydrate diets (LCD) on glycemic regulation among individuals with diabetes mellitus type 2 (T2DM).
Glycemic control is crucial for T2DM patients, as it supports achieving and maintaining glycemic targets and optimizing health outcomes. Carbohydrate reduction and counting are essential for improved self-management in T2DM patients.
Studies have reported that online interventions, such as LCDs, which reduce carbohydrates to less than 26% of total calorie intake, have improved clinical outcomes and glycemic control. However, randomized clinical trial (RCT) data on the effects of online LCD interventions on glycemic control are limited.
About the study
In the present study, researchers investigated whether an online LCD program coupled with regular care practices could improve glycemic regulation among T2DM patients.
During the COVID-19 pandemic, the researchers performed a two-arm parallel-design randomized controlled study remotely among the Australian general public. Adult T2DM patients were included in the study if they: had HbA1c values of 7.0% or above within six months of enrolment; were not on insulin; were aged 40 to 89 years; spoke English; had internet access; and had an active mail address.
For 16 weeks, individuals were randomly allocated in a 1:1 ratio to either the online T2Diet LCD awareness program and regular care group (intervention) or the regular care-only group (control).
The prime study outcome was HbA1c (glycated hemoglobin). Body weight, anti-glycemic drugs, body mass index (BMI), self-efficacy, and nutritional intake were all secondary research outcomes. The Medication Effect Score (MES) was used to quantify changes in anti-glycemic drug potency and dose. Self-efficacy was measured using the Diabetes Management Self-Efficacy Scale (DMSES) and dietary consumption was measured using 24-hour recalls.
Individuals were excluded if they: had other types of diabetes; were vegetarian or vegan; had undergone bariatric surgery; were diagnosed with renal or cardiovascular diseases; were pregnant or lactating; were on a weight loss program or had participated in a weight loss program within three months of enrolment; were enrolled in other clinical studies; were at risk of disordered eating as assessed by the Eating Attitudes Test-26; or had baseline HbA1c levels of 5.6% or higher.
Web-based guidelines supported 50 to 100 grams of carbohydrate intake per day, with ad libitum intake of nutrient-dense lower-carbohydrate foods, with a focus on non-starchy vegetables and dietary fiber, and a reduction in starches, discretionary foods, and sugar.
Participants were recruited through community groups, collegial networking, and social media, including Facebook advertising, between 1 February and 10 October 2021 and were followed up until 18 February 2022. An exploratory analysis was performed to assess diabetes-related comorbidities. A generalized estimating equation (GEE) model was used to estimate the intervention effects.
In total, 98 individuals were enrolled, 49 in both groups, with 87 individuals (40 and 47 individuals in the dietary intervention and control groups, respectively) included in the outcome analyses. The mean values for the participant age, HbA1c levels, weight, and BMI were 61 years, 7.7%, 100 kg, and 35 kg/m2, respectively. Anti-glycemic drugs were used by 74 (85%) of the individuals.
At week 16, significant differences were observed between the groups favoring intervention group individuals, with a 0.7% drop in HbA1c levels, 3.3 kg weight loss, 1.1 kg/m2 BMI reduction, and a 0.4-point reduction in anti-glycemic prescription needs, all with high effect sizes.
Among intervention group individuals, 14 (38%) dropped five percent or more of their body weight, in comparison to three (nine percent of the control group individuals).
Anti-glycemic medicine needs were reduced by 20% or more among seven (25%) intervention group individuals but increased among controls. No statistically significant variations were observed in diabetes-related comorbidities between the two groups. Most intervention group participants (85%) followed the dietary intervention as prescribed.
Self-efficacy improved by 7.0 points on average in the intervention group and declined by 1.1 points on average in the control group; however, the difference was not statistically significant between the groups. No statistically significant variations were observed in the consumption of calories, proteins, dietary fiber, or saturated fats across groups.
Total fat consumption, on the other hand, showed a statistically significant intra-group difference. Individuals in the dietary intervention group considerably increased their consumption of monounsaturated and polyunsaturated fats.
Concerning the negative consequences of carbohydrate restriction, one intervention group individual reported constipation over many days after starting LCD, while another reported moderate hypoglycemia, and both cases were self-handled.
Overall, the study findings showed that the T2Diet program significantly improved clinical outcomes and glycemic control among adult T2DM patients as an adjunct to conventional therapy, consistent with previous meta-analyses of in-person LCD dietary interventions for T2DM.
Furthermore, the findings emphasized the potential for online nutritional support and education to increase availability and access for T2DM patients to achieve glycemic control and improve health.