Losing weight can REVERSE most cases of type 2 diabetes

Losing weight can reverse most cases of type 2 diabetes because the condition is more likely to be caused by obesity than genetics, a study has found.

Researchers looked at almost 500,000 people in the UK and if they had genes tied to the disease. They also measured their body mass index (BMI).

Those in the highest BMI group, categorised as severely obese, had an 11-fold increased risk of type 2 diabetes compared to participants within the healthy weight range.

This was regardless of whether they had genes linked with the disease, showing BMI to be the most powerful risk factor. 

The study also showed it didn’t matter how long someone had been overweight for, rather, they had crossed their own threshold of healthy risk-free weight.

Everyone will have a different threshold at which they start to develop abnormal blood sugar levels, the researchers said.

Therefore keeping weight below that will help to prevent or reverse the condition.

It is known the most successful way of putting type 2 diabetes into a remission state is to lose weight, with the Mediterranean diet or a low-carb diet being encouraged by doctors. 

Most cases of type 2 diabetes can be reversed because they are more likely to be caused by obesity than genetics, a study has found 

In 2019, approximately 463million people worldwide had diabetes, including 4.7million in the UK and 34.2million in the US.

The vast majority (around 90 per cent) are type 2 diabetes, rather than type 1, which have risk factors including obesity. Genetic make-up may also identify individuals with a greater likelihood of developing the condition.

More people than ever are at risk of type 2 diabetes, according to charities, and cases are expected to reach 5million in the UK in five years time in line with rising obesity prevalence. 


Body mass index (BMI) is a measure of body fat based on your weight in relation to your height.

For children and young people aged 2 to 18, the BMI calculation takes into account age and gender as well as height and weight.

Ethnicity can also affect the risk of some health conditions. For example, adults of Asian origin may have a higher risk of health problems at BMI levels below 25.

Standard Formula:

BMI = (weight in pounds / (height in inches x height in inches)) x 703

Metric Formula:

BMI = (weight in kilograms / (height in meters x height in meters))


Under 18.5: Underweight

18.5 – 24.9: Healthy

25 – 29.9: Overweight

30 or greater: Obese 

Principal investigator the study, Professor Brian Ference of the University of Cambridge, UK, and University of Milan, Italy, said: ‘Because we are born with our genes, it might be possible to pinpoint early in life who has a high chance of developing diabetes during their lifetime.

‘We conducted this study to find out if combining inherited risk with current body mass index (BMI) could identify people at the highest risk of developing diabetes. Prevention efforts could then concentrate on these individuals.’ 

The study of 445,765 participants of the UK Biobank saw people divided into five groups according to genetic risk of diabetes and five groups according to BMI.

Inherited risk of diabetes was assessed using 6.9million genes. Participant’s height and weight were measured at enrolment to calculate their BMI. 

By a standard rule of thumb, people with a BMI of 25 to 29.9 are overweight, and those with a BMI over 30 are obese. 

But there is no specific BMI number at which type 2 diabetes is likely to occur, although is known to be lower in black, Asian and other minority ethnic groups. 

Participants, just over half of whom were women, had an average age of 57 and were followed up until an average age of 65.

During that period 31,298 (seven per cent) of them developed type 2 diabetes.

Those in the highest BMI group, with an average of 34.5, had an 11-fold increased risk of diabetes compared to the lowest BMI group, with an average of 21.7, researchers said at a virtual briefing of the annual European Society of Cardiology (ESC) Congress.

This was even if those with a high BMI did not have genetic risk.

‘The findings indicate that BMI is a much more powerful risk factor for diabetes that genetic predisposition,’ said Professor Ference.   

Investigators also discovered that the length of time a person had a higher BMI did not have an impact on the risk of diabetes.


It is possible to put type 2 diabetes into ‘remission’, when blood sugar levels are below the diabetes range and the patient no longer needs to take medication.

The term ‘reversed’ is not often used because it implies cured. But there is no guarantee a person who has had type 2 diabetes is free from the disease forever.

The strongest evidence for reaching type 2 diabetes remission points towards weight loss in people who are carrying extra weight or have obesity.

Scientists believe that storing too much fat in the liver and pancreas affects how type 2 diabetes develops and losing this fat can help put the disease into remission, according to Diabetes.org.

The website says: ‘In fact, losing around 15kg significantly increases your chances of type 2 diabetes remission.’

It’s easier to get diabetes into remission closer to the time of diagnosis. 

Professor Ference said: ‘This suggests that when people cross a certain BMI threshold, their chances of diabetes go up and stay at that same high-risk level regardless of how long they are overweight.’

Most cases of the disease could either be prevented or reversed if someone’s BMI was kept below their personal cut-off point at which abnormal blood sugar levels are triggered, Professor Ference said.  

Everyone will have a different threshold which sees them at risk of becoming diabetic, explaining why some people with a healthy weight develop the condition and some who are overweight do not, he added.     

Explaining further the significance of the study, he said: ‘You can prevent most cases of diabetes by keeping BMI below a person’s threshold.

‘But it (the study) also implies something that we haven’t focused on in the past and that is we can also probably reverse most cases of diabetes if we lower somebody’s BMI aggressively below their BMI threshold relatively soon after they develop diabetes.

‘I think the fact that BMI appears to have a threshold rather than a cumulative effect on the risk of diabetes really has potentially significant implications for how we think about changing screening, preventing, treating and reversing diabetes.’

Professor Brian Ference said the findings of the study could have ‘significant implications’ for the approach to screening for, preventing, treating and even reversing the condition. 

He said by the end of this year or early next year, the team might make a breakthrough in working out how to estimate what each individuals diabetes BMI threshold is. 

The British Heart Foundation (BHF) said the findings highlight the need to regularly measure BMI and track blood sugar levels of people at high risk.

Professor Jeremy Pearson, the organisation’s associate medical director, said: ‘This important study of nearly half a million people shows that BMI is a more vital risk factor for type 2 diabetes than we previously realised.

‘When someone’s BMI goes above their personal threshold, blood sugar levels increase, triggering the onset of type 2 diabetes, which can lead to damaged blood vessels and increased risk of developing heart and circulatory diseases.

‘If you are overweight, making small, long-term changes to your lifestyle such as reducing portion sizes and being more physically active can help lower your BMI, which is good for your heart and blood vessels.’