Adults are at risk of developing Type 2 diabetes if they can no longer fit into the jeans they wore when they were 21, an academic has said.
Presenting data to a leading diabetes conference, Professor Roy Taylor of Newcastle University in England said such people were “carrying too much fat”.
He presented data at the Annual Meeting of the European Association for the Study of Diabetes on a small study that found that people of normal weight with Type 2 diabetes could “achieve remission” by losing weight.
He said that eight in 12 people managed to “get rid” of their condition by losing 10 to 15 per cent of their body weight.
The participants, who all had the condition despite having a “normal” body mass index, managed to reduce the levels of fat in the liver and pancreas, and the activity of the insulin-producing cells in the pancreas was deemed to be “restored”.
Professor Taylor, principal investigator, said: “Doctors tend to assume that Type 2 diabetes has a different cause in those who aren’t overweight.
“This means that, unlike those who are overweight, those who are of normal weight aren’t usually advised to lose weight before being given diabetes drugs and insulin.
“Instead, there’s a tendency to start them on insulin and other medication at a much earlier stage.
“What we’ve shown is that if those of normal weight lose 10-15 per cent of their weight, they have a very good chance of getting rid of their diabetes.”
The participants in the study, who had an average BMI of 24.5, followed a weight loss programme that included a low-calorie liquid diet for two weeks, in which they consumed only 800 calories a day through soups and shakes.
This was followed by four to six weeks in which they received support to maintain their new weight.
They completed three rounds of this programme until they lost 10 to 15 per cent of their body weight.
After weight loss was achieved, scans showed reductions in the fat in the liver. Eight of the 12 participants had their type 2 diabetes go into remission, which was defined as having blood sugar levels under control and patients no longer needing any medicine.
“These results, while preliminary, demonstrate very clearly that diabetes is not caused by obesity but by being too heavy for your own body. It’s due to having too much fat in your liver and pancreas, whatever your BMI,” Professor Taylor said.
“In the liver, this excess fat prevents insulin from working normally. In the pancreas, it causes the beta cells to stop producing insulin.
“As a rule of thumb, your waist size should be the same now as when you were 21.
“If you can’t get into the same size trousers now, you are carrying too much fat and therefore at risk of developing Type 2 diabetes, even if you aren’t overweight.”
Dr Ahmad Al-Mrabeh, the study’s first author and co-investigator, said: “Weight loss by calorie restriction is powerful in achieving remission of Type 2 diabetes and it is remarkable to have 67 per cent remission in this non-obese group.”
Those attending the online meeting also heard data on another study, which found that the amount of fat stored in the liver is higher in people with Type 2 diabetes, whatever their BMI.
It has previously been suggested that excess fat stored in the liver and pancreas drives the development of Type 2 diabetes and that loss of this fat is central to remission.
Researchers, led by the team at Newcastle, examined two groups of patients following a weight-loss programme, with scans used to measure levels of fat in the liver and pancreas before and after weight loss.
Liver and pancreatic fat were higher in those with diabetes, whatever their BMI, and these levels fell with weight loss.
The researchers suggested that seemingly “healthy” levels of liver fat can trigger Type 2 diabetes.
They said that the way liver fat is assessed should change, to also take patients’ BMI into account.
A separate study presented to the meeting suggested that people who are “healthy obese” – obese people who do not have any problems with high blood pressure, blood fats or diabetes – are not at a greater risk of heart attack or stroke than healthy people of a normal weight. But people in this group are more likely to develop heart failure.
The study authors tracked data on about three million French people, including more than 270,000 who were obese, for at least five years.
People deemed to have “metabolically healthy obesity” had a 34 per cent increased risk of heart failure and a 33 per cent higher risk of developing atrial fibrillation.
They did not appear to be at higher risk of heart attack, stroke or cardiovascular death than metabolically healthy people of normal weight.