What predicts drug-free type 2 diabetes remission? Insights from an 8-year general practice service evaluation of a lower carbohydrate diet with weight loss

“we examine real-world data from a cohort based in a UK primary care clinic offering a low-carbohydrate approach to people with T2D [type 2 diabetes] from 2013 to 2021. The physiological mechanisms behind remission induced by dietary weight loss were first demonstrated in 2011. Since then the idea of drug-free T2D remission has gained international momentum. [..]

Advice on lowering dietary carbohydrate was offered routinely by our team of nine specially trained GPs and three practice nurses to patients with T2D (defined as HbA1c >48 mmol/mol on two occasions) starting in March 2013. Our protocol includes important information around the deprescribing of both drugs for BP [blood pressure] and T2D; both BP and blood glucose were often found to improve to an extent requiring a medication review. Checking and discussing body weight was the first step in every consultation, then the low-carbohydrate diet was offered as an option alongside clear and simplified explanations of key physiological principles emphasising: that good diabetic control is about avoiding the damage caused by blood sugars spikes, that ‘time in range’ matters, a high blood sugar is often a reflection of foods eaten recently, glucose and insulin levels change in response to different foods, starchy carbohydrates comprise many glucose molecules causing significant blood sugar elevation and how weight loss was part of the process.

We view high blood sugars as an interesting puzzle rather than a problem, one to be explored collaboratively with the patient. In cases where weight or HbA1c began to climb after an initial improvement we observed early on that most patients had actually increased their carbohydrate consumption (carb creep). Often a quick telephone call would motivate change. [..]

For those who opted for the lower carbohydrate programme, baseline weight and blood results were ascertained alongside dietary advice as part of routine GP or practice nurse consultations. Weight was measured at each visit, the level of ongoing support was tailored to patient choice and clinical need. In addition to 10 min ‘one-to-one’ appointments (we estimate an average of three consultations per patient, per year) the practice offered optional 90 min evening group sessions, approximately every 6 weeks. Group sessions included relatives who were encouraged to attend as some patients relied on others for food shopping or cooking. Group sessions provided a forum for people to offer practical support to others and training new staff. On average 25 patients attended each session. From the onset of the COVID-19 pandemic, these group sessions were hosted as online Zoom meetings. This enabled us to send a link to these meetings inviting every person in the practice with T2D. This was particularly important for patients wanting a ‘refresher’.

Educational resources were produced to support patients and staff. The low-carbohydrate diet sheet outlines suitable sources of food. Glycaemic load data were also presented to encourage a reduced intake of sugary and starchy foods. For example, replacing breakfast cereals, rice, bread and potatoes with, full-fat dairy, eggs, green leafy vegetables, meat, fish, berries and nuts (with sensitivity to each patient’s sociocultural dietary needs and preferences). From 2018, staff training was formalised through completion of a Royal College of General Practitioners e-learning module on T2D and the glycaemic index, written by one of the authors. [..]

 The tendency for results to deteriorate after initial promise led to us focusing on effective maintenance of dietary change. We suggested people look ahead to the challenges of holidays, Christmas and birthdays, times when so many diets fail. We encouraged patients to look out for weight gain at these times and take action. Computer generated graphs of all metrics measured were sent out as patient feedback (the reception staff call this ‘The happy post’). Around 2016, we became aware of another possible behavioural factor causing our patients to regain weight: ‘food addiction’. In response, we supported people to identify and completely avoid their ‘trigger foods’. [..]

For the whole cohort commenced on the low-carbohydrate programme median (IQR) weight fell from 97 (84–109) to 86 (76–99) kg, giving a mean(SD) weight loss of −10 (8.9) kg; p<0.001. [..] The median (IQR) systolic BP dropped from 140 (134–150) to 132 (122–138) mm Hg; p<0.001. The median (IQR) total cholesterol decreased from 4.9 (4.1–5.7) to 4.3 (3.6–5.0) mmol/L ;p<0.001. [..]

Baseline median (IQR) for time since diagnosis was 2 (0.0–68) months for the remission group compared with 72 (28–127) months for the non-remission group (p<0.001). The remission group were more likely to be diagnosed recently and have a significantly lower baseline HbA1c. All other baseline metrics: age, weight, blood lipids and BP were not significantly different between remission and non-remission groups. [..]

 In the first year after diagnosis 77% of those given low-carbohydrate advice achieved a HbA1c of<48 mmol/mol while not taking any diabetic medication. The comparable figures for established T2D were 35%, 31%, 44% and 20% for durations of 1–5, 5–10, 10–15 and greater than 15 years. By April 2021, 94 people had achieved remission, this was 51% of those choosing a low-carbohydrate approach and 20% of the total practice T2D disease register. [..]

The T2D remission rate at the Norwood surgery has improved every single year since 2017 [..]. We are becoming increasingly effective. Why is this? We believe that offering hope of a better future is essential, coupled with clear messages delivered by supportive peers and professionals. Follow-up with honest feedback is essential. A very helpful motivational technique is to offer our patients dietary change as an alternative to lifelong medication. Interestingly, when offered this choice not a single person in 8 years chose lifelong medication but renewed their dietary efforts. [..]

The role of weight loss in remission is important. Our findings support this, with none achieving remission without weight loss. A commonly reported patient finding was how surprised they were not to feel hungry on this diet. Interestingly randomised controlled trials have shown a low-carbohydrate diet may both increase energy expenditure and reduce appetite, which would make weight loss much easier. The studies which have revealed the physiological changes underlying remission demonstrate the considerable reduction in liver fat content associated with weight loss. In a primary care series of people apparently free of liver disease, liver fat decreased from the very high level of 16.0% to just 3.1%. This completely reverses the liver insulin resistance which causes fasting hyperglycaemia. It also resulted in a sharp reduction in exported triglyceride from the liver to all ectopic sites including the pancreas. This decrease in pancreatic fat supply permits relief of the metabolic stress which causes beta cell dysfunction. It is likely that weight loss by any means can induce remission. Other studies of remission have used a relatively high carbohydrate, low calorie approach and clinical studies of food-based approaches or bariatric surgery both achieve remission. The question is which approach is safe, effective and most acceptable to patients? The present data demonstrate a highly effective method in primary care which allows continued avoidance of weight regain. In a study of adults with screen-detected T2D, weight loss of ≥10% early in the disease was associated with a doubling of remission at 5 years.

The rising cost of drug treatments for T2D is of great concern, especially in an ageing population and an obesity epidemic. The substantial prescribing savings documented in this audit are therefore of profound importance. It is clear that medication will be required for many people with T2D especially those with longer duration disease. However, The National Institute for Health and Care Excellence guidelines on T2D focus more on medication while paying scant attention to diet. The management of most diseases is based on knowledge of pathophysiology but this new understanding of the nature of T2D has not yet been incorporated into such guidelines. Change is underway, guided by the National Health Service (NHS) England diabetes remission programme. Major national savings in prescribing costs for T2D are achievable. It is also important to appreciate the potential risks of some medications. SGLT2 inhibitors can cause potentially fatal ketoacidosis.”

Full article, D Unwin, C Delon, J Unwin, S Tobin and R Taylor, BMJ Nutrition, Prevention & Health, 2023.1.2

The researchers’ low-carbohydrate diet sheet:

  • Sugar – cut it our altogether
  • Reduce starchy carbs a lot: cut out the “white stuff” like bread, rice, pasta, potato, crackers and cereals
  • All green vegetables/salads are fine
  • Fruit is trickier: avoid tropical fruits like bananas, oranges, grapes, mangoes or pineapple (too much sugar); Apples, pears and berries (blueberries, raspberries and strawberries) are fine.
  • Eat healthy proteins: non-processed meat like chicken or red meat, eggs (three eggs a day is not too much), fish – particularly oily fish such as salmon, mackerel or tuna – can be eaten freely. Plain full fat yogurt can makes a good breakfast with berries. Processed meats such as bacon, ham, sausages or salami are not as healthy and should only be eaten in moderation.
  • Healthy fats are fine in moderation: olive oil, butter and coconut oil are good; margarine, corn oil and vegetable oil are not good.
  • Cheese only in moderation
  • Snacks: to be avoided. If you must snack, consider unsalted nuts and an occasional treat of dark chocolate (>70% cacao)
  • Alcohol is full of carbs

Typically, a low carb diet contains less than 130 grams of carbohydrates per day.