Obesity can be split into four different types, scientists claim.
Researchers analysed the success of weight loss surgery, which can be risky, among 2,400 obese people in the US.
Using the results, they were able to create four distinct groups of obesity – and they found weight loss surgery worked differently among them all.
They hope their discovery that there ‘isn’t one magic bullet for obesity’ will help to develop more personalised weight-loss treatments.
Using the results, they were able to create four distinct groups of obesity – and they found weight loss surgery worked differently among them all
The four groups, which have yet to be officially named by the Brown University team, differ in everything from diabetes rates to the prevalence of binge eating.
In group one, dubbed the diabetes group, patients had low levels of so-called ‘good’ cholesterol and high levels of diabetes.
Those in group two (disordered eating) were most likely to have unhealthy eating habits, while those in group four (early onset) were most likely to have been obese since childhood.
The scientists, led by epidemiologist Alison Field, were unable to define distinct characteristics of group three (mixed).
Groups two and three particularly benefited from going under the knife, according to the study published in the journal Obesity.
Those with unhealthy eating habits lost the most amount of weight, at an average of 28.5 per cent for the men and 33.3 per cent for the women.
‘There probably isn’t one magic bullet for obesity – if there is a magic bullet, it’s going to be different for different groups of people,’ Ms Field said.
‘We need to recognise this diversity, as it may help us to develop more personalised approaches to treating obesity.’
Graph shows the weight change percentage patterns among the different types of obesity for men who underwent Roux‐en‐Y bypass surgery – with it proving more effective for those in group two and three
This graph shows the same weight change percentage patterns among the different types of obesity for women who underwent Roux‐en‐Y bypass surgery
Another graph shows the weight change percentage patterns among the different types of obesity for men who underwent gastric banding, which uses a silicone ring to create a small pouch at the top of the stomach
This graph shows the weight change percentage patterns among the different types of obesity for women who underwent gastric banding
WHAT ARE THE FOUR TYPES OF OBESITY?
The four groups, which have been uncovered by the Brown University researchers, differ in everything from diabetes rates to the prevalence of binge eating.
GROUP ONE: Diabetes
- Low levels of high-density lipoprotein, so-called ‘good’ cholesterol
- High levels of glucose in their blood prior to surgery
- Around 98 per cent of patients in this group had diabetes
GROUP TWO: Disordered eating
- Disordered eating behaviours, such as binge eating
- Around 60 per cent reported feeling a loss of control over grazing – eating food between meals. And 92 per cent reported eating when they weren’t hungry
GROUP THREE: Mixed
- Very low levels of disordered eating – just seven per cent reported eating when they weren’t hungry
- No other factors distinguished this group
GROUP FOUR: Early onset
- Obese since childhood
- Group had the highest BMI at age 18, with an average of 32 – the others were around 25
- Also had the highest pre-surgery BMI, an average of 58 – the others were around 45
In the first study of its kind, researchers analysed patients who underwent weight-loss surgery between March 2006 and April 2009.
Some of the patients had a gastric bypass, which involves using surgical staples to create a small pouch at the top of the stomach so a person feels fuller quicker and absorbs less calories.
Others had a gastric band, which uses a silicone ring to create a small pouch at the top of the stomach.
Using an advanced computer model, known as a latent class analysis, the researchers identified four distinct patient subgroups among the participants.
In group one, patients had very low levels of so-called ‘good’ cholesterol and had high amounts of glucose in their blood.
An analysis showed 98 per cent of the patients were diabetic, compared to just 30 per cent on average in other subsets.
Group two was defined by its members’ unhealthy eating habits, with 37 per cent claiming to have a binge-eating disorder.
Some 61 per cent also felt unable to stop themselves from ‘grazing’ between meals, while 92 per cent ate even when they were not hungry.
The researchers were then particularly surprised to discover that those in group three did not have especially worrying eating habits despite them being obese.
Just seven per cent reported eating when they were not hungry compared to 37 per cent in group one, 92 per cent in group two and 29 per cent in group four.
‘Interestingly, no other factors distinguished this group from the other classes,’ the authors wrote.
Group four was made up of people who had been obese since they were children.
By 18 years old, this group had the highest BMI with an average of 32 compared to around 25 for the other three subsets. A BMI of more than 30 is considered obese, while 25 plus is overweight.
Group four also had the highest pre-surgery BMI, averaging at 58 compared to the others’ 45.
‘A child who becomes very obese by age five is going to be very different from someone who gradually gains weight over time and at age 65 is obese,’ Ms Field said.
The researchers hope their findings will help them identify patients who would benefit most from weight-loss surgery.
‘One of the reasons why we haven’t had stronger findings in the field of obesity research is that we’re classifying all of these people as the same,’ Ms Field said.
‘It may very well be there are some incredibly effective strategies out there for preventing or treating obesity.
‘But when you mix patients of different groups together, it dilutes the effect.’
Ms Field added scientists should investigate how varying obesity treatments affect different patients.
For instance, mindfulness may be effective in those who become overstimulated by the sight or smell of food but not those who do not eat when they are not hungry.
Ms Field hopes future studies will also delve into if similar subgroups exist among people who are overweight but not obese.
|DIABETES||DISORDERED EATING||MIXED||EARLY ONSET|
|% WITH OVERWEIGHT MOTHERS||27.1%||29.0%||30.7%||37.4%|
|% WITH OVERWEIGHT FATHERS||35.0%||37.8%||32.2%||40.5%|
|% WITH TYPE 2 DIABETES||97.8%||27.1%||31.2%||38.5%|
|% WITH BINGE EATING DISORDER||19.8%||36.6%||1.9%||10.2%|
|% THAT ARE NIGHT EATERS||14.1%||26.0%||12.1%||14.0%|
|% THAT ARE GRAZERS||37.0%||92.4%||7.2%||29.3%|
|AVERAGE BLOOD GLUCOSE||246.5||97.0||98.0||97.0|
|AVERAGE LDL CHOLESTEROL||107.5||114.0||108.0||100.5|
|AVERAGE HDL CHOLESTEROL||37.0||44.0||43.0||40.0|
|Glucose average – 72 to 99 mg/dL||LDL cholesterol should be less than 100 mg/dL||HDL cholesterol levels should be higher than 40 mg/dL|
IS WEIGHT LOSS SURGERY RISKY?
Obesity affects around 35 per cent of men and 40.4 per cent of women in the US. In the UK, a quarter of the population is carrying a dangerous amount of weight.
This put them at risk of conditions such as type 2 diabetes, heart disease, stroke and even certain cancers, including breast and bowel.
In the US, Medicare and Medicaid generally cover weight-loss surgery if is deemed to be medically necessary and a patient fits a long list of criteria.
The NHS offers the operations for those with a BMI of 40 or above who have tried dieting and exercising without success, and who are willing to make lifestyle changes after going under the knife.
Like all operations, weight-loss surgery can lead to blood clots and wound infections.
There is also the chance that a gastric band may slip or food may leak into the abdomen and cause a serious infection.
Malnutrition can also occur if surgery makes it harder for the gut to absorb nutrients from food.
Patients may also be left with excess folds of skin around their breasts, torso, hips and limbs, which may require surgery to remove.
Around one in 1,400 people who go under the knife to help them lose weight even die during or after the procedure due to complications.