If you weigh more than you should, you’re not alone. People everywhere weigh more than they did a decade ago. In fact, the rate of obesity has doubled over the past 30 years.
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This may be why heart disease remains the world’s leading killer. Multiple studies have confirmed the connection between obesity and death in men and women alike.
“As your body-mass index (BMI, a measurement of obesity) goes up, your risk of dying increases,” says preventive cardiologist Haitham Ahmed, MD, MPH.
In the Nurses Health Study, the risk of death rose 10% in those who moved from a normal BMI to the overweight category. That risk rose by 20 to 30% when they moved into the obesity category. In those with Category III obesity, the risk of death rose by nearly 100%, and cardiac death was four times that of a person with normal BMI.
There are exceptions
There is at least one group of patients for whom obesity has not been associated with harm: those with heart failure. Patients with heart failure who are underweight or have a normal BMI may be more likely to die than those who have obesity.
While those who have obesity who develop heart failure live longer with the disease, they tend to develop heart failure at a younger age and die younger than heart-failure patients of normal weight.
Why obesity is dangerous
Researchers aren’t sure what makes obesity dangerous. They think it’s not the fat itself, but that the fat worsens other risk factors. “In this respect, extra weight doesn’t directly cause heart attacks, but it facilitates other interactions that can,” says Dr. Ahmed. “High cholesterol, high blood pressure, diabetes and smoking cause plaque to build up in the arteries. We think obesity interacts with these other risk factors to make plaque build up faster.”
4 ways excess weight increases risk
Extra weight triggers insulin resistance, which creates a dangerous cycle that can spiral out of control.
The more fat you have, the more insulin resistant you become. This causes your body to secrete more insulin, which makes you store fat. Then you become more insulin resistant, make more insulin, store more fat, and before you know it, you have metabolic syndrome or diabetes, which nearly triples the risk of heart attack and stroke.
Body fat also affects blood lipid levels. The more you weigh, the higher your LDL and triglyceride levels and the lower your levels of beneficial HDL cholesterol are likely to be.
Blood pressure rises when the heart has to pump harder to deliver blood to a growing network of arteries in a larger body. Over time, the struggling heart muscle becomes thicker, increasing the risk of developing heart failure and arrhythmias.
Additionally, people with obesity also have sleep apnea, which causes them to stop breathing up to hundreds of times a night. Sleep apnea increases the risk of heart attack or death by 30% in only four or five years. People who suffer from sleep apnea tend to feel hungry, gain weight from snacking and have trouble losing weight when they try.
How much should you weigh?
That’s a hard question to answer since it’s really determined by your height and muscle mass.
That’s why BMI was developed. To calculate your BMI, divide your weight in pounds by your height in inches squared and multiply the number by 703. A BMI of 18.5 and 24.9 is considered normal, 25-29.9 is having overweight, 30 to 35 is having obesity and 36 or more is having Class III obesity (formerly called morbidly obese).
Or measure your waist
There’s an easier way to determine whether you are overweight. Simply take out a tape measure and measure your waist right above the hip bones.
“Fat in the central abdominal area is an additional risk factor for heart disease, as it accelerates atherosclerosis,” says Dr. Ahmed. “If you’re a man with a waist measuring 40 inches or more, or a woman with a waist of 35 inches or more (less, if you are Asian), you are at increased risk for heart disease and ought to talk to your doctor.”
This article originally appeared in Cleveland Clinic Heart Advisor.