Can type 2 diabetes be reversed by weight loss?

Emma Brown - Nutritionist | 29 Oct, 2020

I'm always on the search for the latest nutrition research, and amazed by the quality of scientific studies that are taking place here in the UK, and around the world. Last week I was lucky enough to hear about some fascinating work straight from the 'horse's mouth' when I attended a conference on diabetes.

Currently in the UK there are 3.9 million people diagnosed with diabetes, and the majority of those (90%) have type 2 diabetes. Scarily this number is set to rise with 1 in 10 of the UK population at risk of developing diabetes by 2030.

One of the key risk factors for developing type 2 diabetes is being overweight – leading to an inability for insulin to work properly, causing raised blood sugars, and the many complications that come with it. Of course, other factors play a part too, including smoking, excess alcohol, lack of exercise and genetic predisposition – but the focus on weight is a key pin point for research.

What's the evidence for weight loss and diabetes?

Weight loss is a bit of a no-brainer when it comes to type 2 diabetes as the results are pretty conclusive – losing weight helps to reduce the risk of developing diabetes even when compared to drug therapies. A wide reaching study completed for the Diabetes Prevention Programme, found a 58% reduced risk in developing diabetes when people were given diet and lifestyle advice (which resulted in weight loss). This was compared to only a 31% decrease in risk for people who were given Metformin, a well-known drug used for blood glucose control in diabetes.

There is no conclusive evidence which type of diet is best, but losing weight, per se, is proven as a very effective way to reduce the risk of diabetes. Whether you choose calorie counting, 5:2, Dukan, Atkins, the choice is yours – but of course, finding the right type of diet to suit you (and to keep the weight off) is equally as important.

But what about if I already have diabetes?

Over the years at Nutracheck we know of members who have lost weight, and either reduced their diabetic symptoms, or in a few cases, completely reversed the condition altogether, but until recently there had been very little research to show whether this was, in fact, a medical 'reversal' or just a result of a healthier lifestyle and better eating.

Diabetes has always been thought to be an irreversible condition, and certainly for type 1 diabetes this appears to be the case. Type 2 diabetes, however, is much more closely linked to weight and lifestyle so the possibility that improvements in these could help have been investigated.

I was fascinated to hear Dr Carl Peters, of Newcastle University, explain the revolutionary work that his team have been involved in, looking at whether type 2 diabetes is reversible.

The team, headed up by Professor Roy Taylor, were interested to see that obese, diabetic patients who had undergone gastric bypass surgery were experiencing a normalising of blood sugars within a week of surgery! They hypothesised that a sudden onset calorie restriction (which occurs after a gastric bypass) normalises the way that the body uses insulin.

Type 2 diabetes results (for the majority of cases) from excess fat in the body (usually through excess weight and body fat) being taken up by the liver and pancreas resulting in a decrease in the sensitivity of the liver to insulin, which in turn increases blood sugar levels, leading to raised insulin levels, which mobilises fat from the cells...and the cycle continues resulting in a diagnosis of diabetes.

So, the team decided to test whether a severe calorie restriction (without gastric surgery) would have the same effect.

What did the scientists do?

Eleven people with diagnosed type 2 diabetes were taken off all their diabetes medication, and then put onto a very low calorie diet (600 kcal/day) for a period of 6 weeks.

The diet consisted of a nutritionally complete milkshake drink, and participants were also encouraged to eat starchy vegetables to support good digestive health.

Participants were studied before, at 1 week, at 4 weeks and at 8 weeks into the study.

What did the results show?

Within 1 week, average weight loss was 4kg – this was probably water and carbohydrate stores decreasing rather than fat loss. HOWEVER, after just one week, blood glucose levels were completely normalised in all patients.

This continued throughout the study, with all patients achieving normal blood glucose readings throughout.

The amazing part of the study for me, was the investigation into liver and pancreatic fat. Before the study the average amount of fat in the liver was 36%. After just one week on a very low calorie diet, liver fat had decreased to just 2%.

Liver function returned to normal which allowed insulin to work in a completely normal way. After 8 weeks, both the liver and the pancreas had returned to fully functioning, and all aspects of physiological abnormality had been reversed.

What about losing weight gradually – would it have the same effect?

Obviously, the methods used in this study are pretty drastic, and although the results are amazing, should we be recommending everyone with type 2 diabetes to lose weight like this? Well the answer is probably no – what we don't know is the longer term effects of this type of diet, nor do we know whether the people on the study have regained weight or whether their diabetes may have returned.

I asked Dr Peters whether losing weight through a sensible calorie deficit (like Nutracheck) would have the same effect. He was pretty clear that, yes, losing weight and body fat by any chosen method would have the same effect – it would just take longer. So you'd be unlikely to see the dramatic and rapid reduction in liver fat, BUT over the process of losing body fat, fat would be lost from the liver and pancreas, and similar reversals in type 2 diabetes could be seen. Subsequent reading about the subject has revealed that opinion is leaning towards a longer term calorie controlled diet to achieve this outcome because it's much more likely the weight will stay off.

What does this mean in the 'real' world?

Well this is obviously brand new scientific research, however, the results are very difficult to argue with. Losing weight (and in particular excess fat in the liver and pancreas) can result in a reversal of type 2 diabetes.

We're not suggesting that everyone goes onto a 600kcal diet, or that we rush to come off all our diabetes medication, but this research is ground breaking in a way that could help to significantly reduce the effects of type 2 diabetes, and to cut down on the scary statistics of what might happen in the next 20 years.

So losing weight gradually, and sensibly, whilst eating a healthy balanced diet, and being as active as possible really may hold the key to reversing type 2 diabetes so it's certainly worth a shot.

If you want to read more about Professor Taylor's research, you can find lots more information here.

Nutritionist Emma Brown (ANutr), MSc Human Nutrition is passionate about how food science applies to the human body, and how the nutrients in what we eat affect us and ultimately have an impact on our health.