Does weight loss cure type 2 diabetes?

Tape measure on blue background, suggesting weight loss

Losing weight could reverse type 2 diabetes, according to the media, but is it true? We look at the research behind the headlines.

6 December 2017

Diabetes occurs when your body doesn’t produce enough insulin or your body is unable to use the insulin that is being produced. Type two diabetes is much more common than type 1 and being overweight is one of the factors that increase the risk of developing this condition.

We already know that losing weight can help you control your type 2 diabetes.

This study, published in The Lancet, investigated the use of a weight management approach which includes a low calorie meal-replacement diet, followed by a transition back onto a healthy diet. In the study participants were supported through this change and to maintain their weight loss gradually by health professionals.

The research

The researchers looked at 30 patients aged 20-65 who had been diagnosed with type 2 diabetes within the past six years (on average, they'd had diabetes for three years), and were not using insulin. They were classed as significantly overweight or obese due to their BMI (body mass index), and they were from Scotland and the Tyneside region of England.

Nearly half of people in the weight loss group had normal blood glucose measurements a year later 

Half of the group were put a strict weight loss programme, called the Counterweight-Plus weight management programme, in which their normal diet was replaced by milkshakes and soups for three to five months, with a maximum 853 calories each day – about a third of the average energy needs of a man and less than half those of a woman. This was followed by a gradual reintroduction of solid food, and support to maintain their weight loss long-term. If they were taking tablets for diabetes, these were stopped at the start of the programme. 

The other half of the group – the ‘control’ group - were given traditional diabetes care, not including the weight loss programme, and continued their medications. 

Nearly half (46 per cent) of people in the weight loss group had normal blood glucose measurements a year later – which would mean that their diabetes was considered to be “in remission”. This is compared to 4 per cent of participants in the control group.  

Among people  who lost more than 15kg (2st 5lb) in the study, more than eight out of 10 (86 per cent) went into remission. In those who lost 10-15kg, more than half (57 per cent) of those who lost 10kg (1st 8lb) to 15kg, and 34 per cent of those who lost 5kg (11lb) to 10kg. No-one who didn’t lose any weight achieved diabetes remission, where their blood glucose levels were normal.

The researchers said that this was because substantial weight loss results in reduced fat inside the liver and pancreas, allowing these organs to return to normal function. 

A strength of the research, which was led by the universities of Newcastle and Glasgow, was that it was a clinical trial using people in real-life settings, rather than animals in a lab, so the results are more applicable to other people with diabetes. It was also a recent trial, carried out from July 2014 to August 2017.

The researchers said that their weight loss programme could be widely used across health services

What this study doesn’t tell us is whether losing weight can still have these effects on diabetes even if you’ve had the condition long term (longer than the six years used in the study.) The study authors say “Existing evidence has shown that remission is less likely with longer durations of disease”. 

The researchers said that the weight loss programme that they used could be widely used across health services.

Interestingly, quality of life, measured with a self-completed questionnaire, improved by 7 points for participants in the weight loss group, and decreased by nearly three points in the group that used medicine. This indicates that weight loss also had non-medical benefits too.

The BHF view

Victoria Taylor, BHF Senior Dietitian, says: “Type two diabetes is a risk factor for heart and circulatory disease and with 50 per cent of participants achieving remission at 12 months this is extremely interesting.

“However, it’s important to be aware that meal replacement is not an easy option and the people in the trial were supervised throughout. If you have weight to lose and are considering this type of approach, make sure you take advice and don’t stop any medication without talking to your doctor first.

“What should also be remembered is that the remission seen in the study participants is dependent on them maintaining the weight loss – it’s not enough to lose weight and then return to previous eating and exercising habits. Instead, the weight loss should be a springboard to a long term lifestyle change.”

The coverage

The study received a lot of attention in the media, with articles from Daily Mail, the Mirror, The Guardian, BBC News, and the Evening Standard, amongst others.

The Mail headline was “Crash diet can REVERSE Type 2 in three months”. This is not strictly accurate as the programme lasted for longer than three months, and the measurements to find out if they still had diabetes were taken after 12 months.

Some of the headlines, such as the Evening Standard, said that this study showed there was a ‘cure’. Type 2 diabetes is a chronic condition, but it can be managed so that your blood glucose returns to a normal level. If the participants put on weight again, the diabetes is likely to come back.

Most of the news coverage did not point out that these results might be less likely in people who had diabetes for a longer period of time. 

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