Empowered Health Course · Lesson 7 · 3:59
Let's start with the definition of obesity, so we all know what we're talking about. The definition has shifted over time. At first it was a body mass index over 30 — a calculation from height and weight. At a population level, when BMI goes above 30, there's some increased risk of health complications. That's the theory behind BMI, but it's useful at a population level, not so much for an individual.
Obesity Canada, one of the leading organizations in this field, developed excellent guidelines and shifted the definition to something truer and more helpful: "Obesity is a chronic, complex disease in which abnormal or excess body fat impairs health, increases the risk of long-term medical complications, and reduces lifespan." Notice there's no BMI in that definition.
Here's why. Imagine someone with a BMI of 35 who has no signs or symptoms of any health concern — walking well, breathing well, sleeping fine, enjoying life, active, with normal blood pressure and no diabetes or pre-diabetes. That is not the disease of obesity; that's a person living in a larger body, and it's not a medical condition. People living in larger bodies don't necessarily have the disease of obesity.
The opposite happens too. I've seen, time and again, a person with a BMI of 27 — or even 25, considered "normal" — who has type 2 diabetes. There it's not excess fat but abnormal function of the fat that leads to the condition. So even with a BMI under 30, someone can be living with the chronic disease of obesity.
So obesity is really two things: symptoms from the mechanical pressures of excess weight, or symptoms from abnormal function of fat cells that leads to metabolic complications — an impaired ability to store energy safely. That's what drives many chronic conditions in our society, like high blood pressure and type 2 diabetes. We'll see you again soon.
This transcript has been lightly edited from the video for readability. For the complete experience, please watch the video above.