Ampath Diagnostic Guide | Pathology solutions are in our DNA
⚖️ What is Obesity?
Obesity is a condition where excess body fat accumulates and negatively impacts health. It’s measured using Body Mass Index (BMI):
BMI = weight (kg) ÷ height² (m²)
BMI Weight Categories:
- < 18.5 – Underweight
- 18.5–24.9 – Healthy weight
- 25.0–29.9 – Overweight
- 30.0–34.9 – Obesity Class I
- 35.0–39.9 – Obesity Class II
- ≥ 40 – Obesity Class III
🩺 Health Impact of Obesity
After the onset of obesity, the body often shows:
- Impaired glucose tolerance
- Increased insulin resistance
- Abnormal lipogram (↑ triglycerides, ↓ HDL)
- High blood pressure
Obesity raises the risk of:
- Heart disease
- Stroke
- Type 2 diabetes
- Gallstones
- Osteoarthritis
- Obstructive sleep apnoea
- Infertility
- Certain cancers
🧬 Causes & Contributing Factors
While rare medical conditions (e.g. hypothyroidism, PCOS, hypercortisolism) can cause obesity, the primary drivers are:
- High-energy diets
- Lack of physical activity
Your doctor can evaluate for secondary causes (e.g. hormonal imbalance, hypothalamic injury, or genetic mutations).
🌍 The Global Picture
- According to the WHO (2014):
- Over 1.9 billion adults were overweight
- 600 million were obese
- Obesity affects 13% of the global adult population
🧒 Childhood Obesity
Declared a “paediatric epidemic” by the American Academy of Paediatrics (2005):
Children are increasingly diagnosed with:
- High blood pressure
- Elevated cholesterol
- Type 2 diabetes
- Joint/bone issues
Obese children are more likely to become obese adults, with shortened life expectancy if the trend continues.
🛡️ Protective Lifestyle Factors
- Regular physical exercise
- High dietary fibre intake
- Low glycaemic-index foods
- Supportive home & school food environments
- Breastfeeding
Refer to Ampath’s “Lipids – Separating fats from fiction” for healthy food guidelines.
🧪 What is Insulin Resistance?
Insulin, secreted by the pancreas, regulates blood sugar.
Insulin resistance = the body becomes less responsive to insulin → higher insulin levels are needed.
Causes:
- Abdominal obesity
- High-carb/high-calorie diets
- Inactivity
- Chronic stress
- Steroids
- Hypercortisolism
- PCOS
- Hereditary factors
Symptoms:
- Fatigue
- Hunger
- Difficulty concentrating
Consequences:
- Increased belly fat
- Hypertension
- High cholesterol
- Type 2 diabetes
- PCOS
- Metabolic syndrome
🔄 What is the Metabolic Syndrome?
It’s not a disease, but a group of interlinked risk factors commonly tied to insulin resistance:
Diagnostic Criteria (IDF 2006):
Must include:
- Central obesity:
- Waist circumference ≥ 80 cm (women)
- Waist circumference ≥ 94 cm (men)
PLUS any two of:
- Triglycerides ≥ 1.7 mmol/L, or on treatment
- HDL cholesterol < 1.3 mmol/L, or on treatment
- Blood pressure ≥ 130/85 mmHg, or on treatment
- Fasting glucose ≥ 5.6 mmol/L, or diagnosed diabetes
These cut-offs are also applicable to Sub-Saharan Africans and other ethnic groups.
💔 Risks of Metabolic Syndrome
- Increased risk of Type 2 diabetes
- Increased risk of cardiovascular disease
- More components present = higher mortality risk
🔬 Laboratory Tests for Diagnosis
- Fasting blood sugar
- Glucose tolerance test
- Lipogram (includes total cholesterol, LDL, HDL, triglycerides)
- Uric acid
🏃♀️ Treatment & Lifestyle Changes
🔹 Lifestyle First:
- Weight loss through:
- Low-carb, high-fibre, or ketogenic diets
- Moderate physical activity: 30–45 min, 3–5 times/week
- Walking, swimming, cycling, gardening, housework
🔹 Additional Interventions:
- Medication for weight loss
- Weight loss surgery for morbid obesity