Healthy Body Weight

Body Mass Index (BMI)

a measure of body fat based on height and weight

BMI

weight (kg) / height (m)

• in m2

BMI Estimates

body fat (not a direct measure)

• can be useful indicator of health risks associated with over and under weight

BMI Advantages

• Simple and quick (low cost)

• Accessible 

• Standardized metric

BMI Disadvantages

• No distinction between fat mass and muscle mass 

• No information on fat distribution 

• Does not consider sex, ethnicity or age 

• Not for pregnant people, children 

• Not a diagnostic tool

Weight Circumference

indicator of health risk associated with excess abdominal fat

Weight Circumference Advantages

• Identifies high-risk visceral fat

• Detects risk of someone has normal BMI 

• Simple 

• Considers sex

Weight Circumference Disadvantages

• Measurement inaccuracy 

• Does not differentiate between muscle and fat

• Less accurate in pregnancy 

• Less accurate in certain ethnic groups: South Asian, Chinese, and Japanes

Canadian Guidelines for Body Weight Classification in Adults

use BMI and waist circumference as indicators of health risk

not intended for those under 18, pregnant and lactating women

Canadian Guidelines for Body Weight Classification

it may underestimate or overestimate health risks in specific groups:

• Young adults who have not reached full growth

• Adults who naturally have a very lean body build 

• Very muscular adults 

• Adults over 65 years of age

• Certain ethnic and racial groups

BMI and WC Cannot be Used to

determine who is healthy and who is not

• Normal weight does not automatically mean someone is healthy

• Overweight/obesity does not automatically mean someone is unhealthy 

What are BMI and WC

screening tools to assess who may be at risk for weight-related illness

• not diagnostic tools

• can be used to identify who may be at increased risk

• can be used to make decisions about referrals (bloodwork, dietician)

Misdiagnoses With BMI

50% of overweight individuals and 30% of obsese individuals were metabolically healthy

over 30% of normal weight people were metabolically unhealthy

many people are classified as unhealthy or healthy based on BMI alone

People in Larger Bodies

can be misdiagnosed

risk of real medical concern being overlooked if focus is place on weight or weight loss

People in Smaller Bodies

can be under-disgnosed

• assumotion of good health

Obesity

serious chronic disease characterized by excessive body fat

Obesity Is

the leading risk factor for heart disease, stroke and type 2 diabetes

What Helps Improve or Prevent Obesity

modest weight loss (5-10% of body weight)

Obesity Influences

genetic, behavioral, metabolic, hormonal

Contributing Factors to Obesity

high caloric intake and less physical activity

What BMI is Classified as Obease

30.0 or higher

Obesity Causes

• Genetics 

• Disease (e.g. hypothyroidism)

• Medications 

• Social and economic issues (e.g. lack of access to healthy food)

• Age

• Lack of sleep 

• Stress

• Microbiome (gut - bacteria)

Obesity Health Risks

• Hypertension or high blood pressure

• Coronary heart disease

• Type 2 diabetes

• Stroke 

• Gallbladder disease

• Osteoarthritis 

• Sleep apnea and other breathing problems 

• Some cancers such as breast, colon, and endometrial cancer 

• Mental health problems, such as low self-esteem and depression

Underweight

weighing less than the expected normal weight

What BMI is Considered Underweight

<18.5

Underweight Can Cause

serious health risks or be a sign of serious underlying conditions

Underweight Can Lead To

• Weakness and fatigue 

• Dizziness or lightheadedness

• Low pulse and BP 

• Hair thinning or hair loss

• Getting sick a lot and taking longer to recover 

• Irritability, apathy or depression 

• Irregular period or missing period 

• Trouble getting pregnant

Underweight Causes

• Limited access to food ($, travel)

• Mental health conditions (e.g. eating or mood disorders)

• Physical difficulties with eating 

• Malabsorption disorders (e.g. celiac disease, IBS)

• Needing extra calories (e.g. overexercising, hyperthyroidism)

Underweight Risk Factors

• Age 

• Economic status 

• Biological family history

Complications of Being Underweight

Anemia, osteoporosis, loss of muscle mass, weakened immune system, growth delays (in children), infertility/pregnancy complications