Diabetes remission is an area of substantial interest among researchers, as diabetes is among the leading causes of death in Western societies (Diabetes UK, 2018; Centers for Disease Control and Prevention, 2022). This is partly owing to lifestyles that involve increasingly easy access to fast food and that are more sedentary, which has not been helped by recent lockdowns throughout the COVID-19 pandemic (Dicken et al, 2021; Public Health England, 2021).
Increasing numbers of studies show remission of diabetes through a reduction in body weight (Quimby et al, 2021). Further research looks at how different food groups affect this chance of remission. Goldenberg et al (2021) aimed to determine the effect and safety of low-carbohydrates diets (LCDs) and very low-carbohydrate diets (VLCDs) for people with type 2 diabetes. This was a systematic review and meta-analysis involving searches of multiple reputable databases, as well as grey literature resources, examining material up to August 2020. The researchers selected randomised controlled trials that evaluated LCDs and VLCDs.
An LCD was defined as carbohydrates making up less than 130 g or less than 26% of a 2000 kcal/day diet, while VLCDs were defined as less than 10% of calories in the person's diet being from carbohydrates. The studies accepted were those covering such diets over a 12-week period for adults with type 2 diabetes.
The primary outcome was remission of diabetes. Remission was defined as having glycated haemoglobin (HbA1c) levels of less than 6.5% or a fasting glucose of less than 7.0 mmol/L, with or without the use of medication for diabetes. Other primary outcomes were weight loss, fasting glucose, and adverse events. Secondary outcomes were health-related quality of life and biochemical laboratory data. The articles gathered were screened independently, extracted and assessed for risk of bias and grade certainty of evidence at 6- and 12-month stages of the patient's follow-up.
The searches identified a total of 14 759 citations, leading to 23 trials, which involved a total of 1357 participants. The researchers determined that 40.6% of outcomes were at a low risk of bias. At 6 months, they found that, when compared with the control group, LCDs were observed to achieve higher rates of diabetes remission. Subgroup assessments were carried out, and these indicated that remission while using an LCD significantly decreased in studies with patients who used insulin. The researchers also found that, at 12 months, data on remission were sparse, ranging from a small effect to a trivial increased risk of diabetes.
However, significant clinically important improvements were seen in weight loss, triglycerides and insulin sensitivity at 6 months, although it is important to note that these diminished at 12 months (Goldenberg et al, 2021a). Using the credible subgroup assessments, the researchers found that VLCDs were less effective than the less restrictive LCDs for weight loss at 6 months. However, this was due to the person adhering to the diet. It was found to be far more difficult to stick with a VLCD, and results produced would thus not be a reliable indicator. Of those in the VLCD group, patients who adhered well to the diet saw significant changes in weight loss, which is known to be effective for diabetes remission, at least in the short term. Participants experienced no significant difference in quality of life at 6 months and no significant or clinically important differences were observed between groups regarding occurrence—for example, of adverse events or blood lipids at 6 and 12 months.
Goldenberg et al (202a) concluded that, on the basis of moderate-to-low certainty evidence, patients adhering to an LCD for 6 months may experience remission of diabetes without adverse consequences. However, the authors argued that limitations exist regarding these data, as it is difficult to determine what exactly constitutes ‘remission’ of diabetes, and it is also challenging to determine efficacy and safety, as well as dietary satisfaction, for those who may require a longer-term LCD.
In defining diabetes remission, three factors are predominantly considered. These are:
- A HbA1c threshold
- Use of antidiabetic drugs
- Duration of remission.
While encouraging diets to induce remission of diabetes, clinicians should always be aware of the risk of the patient ceasing what has otherwise been an effective drug treatment for their diabetes (eg Metformin). Duration of remission has been noted to range from 30 days to 5 years, depending on the reference source.
Generally speaking, if a patient is unlikely to stick to a dietary regimen, the efficacy of introducing it is likely to be poor. This is especially the case for a particularly strict diet, such as a VLCD, which is unlikely to be sustainable in the long term.
It should be seen as high risk to stop medication, and potentially unethical. Further research and a more formal definition of diabetes remission would be helpful in weighing up the benefit-risk ratio of switching from medication to a diet-based regimen; it should be considered whether a combination of the two could safely benefit the patient.
Furthermore, it is worth considering a more nuanced approach to diet in partnership with the patient, where high-energy foods that they enjoy are identified as the basis for a more balanced and sustainable approach.