Fact Sheet: Sex Differences in Obesity

Part 1: Definitions and Epidemiology

Part 2: Effects of Life Stages and Metabolic Hormones

Part 3: Effects of Fat Distribution

Part 4: Obesity’s Impact on Co-morbidities

Part 5: Neural Mechanisms of Appetite and Satiety

Part 6: Effectiveness and Interventions

Definitions

Obesity is usually determined by body-mass index (BMI), which is equal to the weight of a person (in kg) divided by their height (in meters) squared. Significant categories of BMI are:

Weight BMI
Underweight <18.5
Normal Weight 18.5-24.9
Overweight 25-29.9
Obese 30-34.9
Morbidly Obese 35+

Abdominal obesity is determined by measuring waist circumference (WC). Although WC is related to BMI, it is an independent cardiovascular disease (CVD) risk predictor, especially in patients categorized as having normal or overweight BMI. A WC > 35 inches (88 cm) in women and >40 inches (102 cm) in men indicates increased CVD risk across normal to obese BMI categories.1

Other methods of estimating body fat and body fat distribution include measurements of skinfold thickness and WC, calculation of waist-to-hip circumference ratios, and techniques such as ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI).

Epidemiology

Page Last Updated: July 2009