“Nutrition is the single most important lifestyle factor in preventing, treating, managing and reversing type 2 diabetes,” says John H. Kelly Jr., principal investigator of a recent clinical trial comparing a whole-food, plant-based diet (WFPB) with standard medical care (SMC) in people with type 2 diabetes (T2D). The results, published in Diabetologia, show that the WFPB diet led to greater reductions in HbA1c levels, induced diabetes remission, and reduced the need for diabetes and cardiovascular medications.
Plant-based diet shown to control diabetes better than standard medical care
In a recent randomised controlled trial, a whole-food, plant-based diet and exercise intervention was superior to standard medical care in improving glycaemic control, promoted diabetes remission and reduced the need for medication. The results illustrate the potential of lifestyle changes that are often overlooked in favour of medical interventions.
Figure 1: Study design and main results of a randomised controlled trial comparing a whole-food, plant-based intensive lifestyle intervention in people with T2D (hsCRP: high-sensitivity C-reactive protein). Adapted from: CJ Hanick et al, 2024.
Lower HbA1c and fewer medications
The trial was conducted in the Republic of the Marshall Islands, chosen for its high T2D prevalence that has been partially attributed to common unhealthy dietary patterns. At baseline, 61 % of the participants (see Figure 1) received diabetes medication (40 % metformin, 40 % sulfonylurea, 9 % insulin). Patients were randomly assigned to either SMC or WFPB diet plus exercise (PB+Ex). In the SMC group, glucose-lowering therapy as well as dietary patterns and levels of physical activity were maintained. Meanwhile, the PB+Ex group followed a WFPB diet high in fibre, low in fat, moderate in protein and low in sodium, along with moderate-intensity exercise sessions and group classes; medications were adjusted based on glucose levels. Primary outcomes included markers of glycaemic control (HbA1c, glucose, insulin and homeostasis model assessment for insulin resistance [HOMA-IR]) and the use of glucose-lowering medication. Secondary outcomes were lipids, blood pressure, heart rate and C-reactive protein (CRP) levels.
After 24 weeks, HbA1c levels in the PB+Ex group were 8 mmol/mol (0.7 %) lower than in the SMC group, for a total reduction of 16 mmol/mol. In addition, 63 % of PB+Ex participants were able to reduce their glucose-lowering medication, compared to only 24 % in the SMC group (p = 0.006). Also, 23 % of PB+Ex participants with baseline HbA1c levels below 75 mmol/mol (< 9 %) achieved remission. Finally, the PB+Ex group also had greater reductions in weight, CRP and cardiovascular medication use.
Need for individualised diets
Kelly emphasises that the broad and strong epigenetic effects of nutrition on metabolism play a crucial role in diabetes management. However, dietary interventions are particularly effective in people who do not already have a healthy diet, and the approaches need to be personalised. “In my clinical experience, no single dietary pattern works best for every patient with diabetes or insulin resistance. I personally use individualised diets and believe that research will eventually identify the best dietary patterns for different individuals, including the WFPB diet,” he says, also highlighting the added benefits of intermittent fasting using early time-restricted feeding (eTRF) to “supercharge” healthy dietary patterns.
Overall, the study results show that a WFPB diet, combined with regular exercise, is an effective, evidence-based lifestyle option for people with T2D. “A WFPB diet is high in fibre with a lower glycaemic index, which helps reduce caloric intake and promotes a favourable microbiome. Cruciferous vegetables and berries are high in antioxidants, which help ameliorate the negative effects of lipotoxicity, oxidised cholesterol and other harmful metabolic effects of excess caloric intake,” the trial's principal investigator explains.
Expanding research into dietary approaches
While a plant-based diet and regular physical activity are in line with current diabetes guidelines, Kelly notes that in the past, lifestyle changes have often been overlooked in favour of pharmacological treatments. “There is currently an unfortunate disparity between present research-based guidelines and prevailing clinical practice. This will improve as the scientific evidence becomes better known and distributed,” he says. More research is also needed within the field, especially head-to-head comparisons between WFPB and different dietary approaches, such as low-carbohydrate or Mediterranean diets.
Key Points:
- Nutrition plays a key role in the prevention, treatment, management and remission of type 2 diabetes. A randomised controlled trial has now compared a whole-food, plant-based intensive lifestyle intervention with standard medical care.
- At week 24, diet plus exercise reduced HbA1c by an additional 8 mmol/mol (0.7 %) compared with standard medical care.
- 63 % of participants in the diet plus exercise group were able to reduce their glucose-lowering medication, and 23 % with a baseline HbA1c < 75 mmol/mol achieved diabetes remission.
- With the growing evidence from this area of research, other questions are being addressed, such as individualised diets and head-to-head comparisons among different dietary approaches.
To read this paper visit: Hanick CJ, Peterson CM, Davis BC, Sabaté J, Kelly JH Jr. A whole-food, plant-based intensive lifestyle intervention improves glycaemic control and reduces medications in individuals with type 2 diabetes: a randomised controlled trial. Diabetologia. 2024 Sep 21. doi: 10.1007/s00125-024-06272-8.
Author: Hanna Gabriel, BA MSc. Any opinions expressed in this article are the responsibility of EASD e-Learning.