Heavy but healthy? New formula slims down definition of dangerously obese



New Canadian research suggests being obese doesn't necessarily doom people to an early grave.

Two research teams using a new tool called the Edmonton Obesity Staging System, which ranks overweight and obese people on a five-point scale according to their underlying health, have found that not only can the scale predict who is at greater risk of dying, but that otherwise healthy obese people live as long as those of "normal" weight, and are less likely to die of cardiovascular causes.



Under Stage 0, the person is obese, but has no apparent obesity-related health risks, meaning their blood pressure, blood fats and other risks are all within the normal range. Stage 1 obesity describes people with "sub-clinical" signs of trouble, such as borderline high blood pressure, elevated liver enzymes and occasional aches and pains. Stage 4 is the most severe. At Stage 4, patients have serious, "potentially end-stage" disabilities and illnesses from obesity-related diseases.



After adjusting for age, history of smoking and metabolic syndrome — a cluster of conditions such as high blood pressure and diabetes —about two per cent of people with scores of 0 or 1 died during followup, compared to about 40 per cent of Stage 3 patients.

"That's a huge difference," said Dr. Arya Sharma, who first proposed the Edmonton classification system.

"What this actually means is if I examine people today and I see that they're Stage 0 or Stage 1, I can tell them to eat as healthy and be as physically active as possible rather than running out and trying to lose weight," said Sharma, chair of obesity research and management at the University of Alberta in Edmonton.

In a second study, using a modified version of the Edmonton scale, researchers led by York University's Dr. Jennifer Kuk categorized 6,000 obese Americans according to the Edmonton obesity staging system and compared their risk of dying to 23,000 lean individuals over a 16-year span.

They found that obese people with no or only mild health problems had a similar risk of dying over the followup period as normal-weight people. In fact, patients in Stage 0 or 1 were at lower risk of dying from cardiovascular disease or coronary heart disease than normal-weight individuals.

By contrast, people in stages 2 and 3 were 50 per cent more likely to die from any cause than normal-weight people or even the Stage 0's and 1's.

People with higher scores were slightly older, had modestly higher BMIs, were more likely to be former smokers, lost more weight over their lifetime and lost more weight frequently. People with lower scores tended to be more physically fit. They ate more fruits and vegetables. And they were less likely to want to lose weight, Kuk said.

"They were happier with their higher body weight, and they had been obese for a longer period of time as compared to those who were Stage 2 or 3." They had been heavier from a younger age.

The findings not only challenge the notion that everyone who is obese needs to lose weight. "Just because you're normal weight doesn't necessarily mean that you're healthy," Kuk said. "You can still have high blood pressure, you can still have diabetes, you can have a poor lifestyle — and all of these contribute to obviously negative health and early mortality risk."



Body mass index "only measures how big the patient is, not how sick the patient is," says Sharma, founder of the Canadian Obesity Network who co-authored both papers.

When a person's body mass index is above 30, "you're clinically considered to have obesity," says Sharma.

"But when you look at people who meet those BMI criteria, not all of them actually have any health problems."

Sharma says weight-management interventions, including publicly funded bariatric or weight-loss surgery, where waiting lists can stretch years, should be targeted at the people who have the most to gain.

"Obesity treatment is always expensive and its not always easy to do," Sharma said.

Currently, patients with a BMI over 40 are eligible for surgery, "but there are people with BMIs over 40 who are actually pretty healthy," he said. "The question becomes, what's the health benefit of doing that?"

The system is modelled after other staging systems used to determine how sick people are from diseases such as cancer or kidney failure.

"If someone comes to my office and their BMI is 35, they have obesity, there's no question," Sharma said.

"But if I do the tests and I find that they have no other risk factors, then I can confidently tell them that they are at extremely low risk of dying. There shouldn't be an urgent need to lose weight just because their BMI is high. The focus really should be on trying to maintain that weight and not get heavier."

The opposite could hold for people with lower BMI's who don't meet criteria for surgery but who are at high risk and should be treated. "And we're missing those patients," Sharma said.


"If you're constantly dieting and trying to lose weight, and you put it back and you diet again, you might actually be causing problems."

The researchers looked only at the risk of death. Sharma said quality of life, "employability and the discrimination they face from society are also be important in making decisions about obesity treatments."




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