Overweight vs Obesity: What’s the Difference?
The terms "overweight" and "obesity" are often used interchangeably, but they actually refer to different conditions. Both involve excess body fat, but with different implications for health.
In Italy, 11.8% of the adult population is obese, and the phenomenon is growing among young people: in the 18-34 age group, cases increased from 5% in 2022 to 6.6% in 2023 (source: ISTAT data).
Obesity is not just about weight: it is a risk factor for numerous diseases, including cardiovascular diseases – the leading cause of death worldwide – and various forms of cancer. For this reason, it’s crucial to keep track of your weight and understand the impact it can have on your health.
Let’s explore the difference between overweight and obesity, how they are determined, and the consequences they can have.
What’s the Difference Between Overweight and Obesity?
Overweight and obesity are both conditions characterized by excess body fat, but they differ in severity and health impact.
Overweight refers to a weight that is above normal but is not considered a disease. However, it can be an alarming sign not to ignore. Obesity, on the other hand, is a true medical condition associated with an increased risk of chronic diseases and has physical, psychological, and social consequences.
How Are Overweight and Obesity Measured?
There are various methods for determining whether a person is overweight or obese. Some of the most commonly used methods by doctors include:
Body Mass Index (BMI)
BMI is calculated by dividing weight (in kilograms) by the square of height (in meters). This value is widely used to classify body weight and assess potential health risks. Although it only provides an estimate of body fat, it helps identify various weight categories:
- Underweight: BMI less than 18.5
- Normal weight: BMI between 18.5 and 24.9
- Overweight: BMI between 25 and 29.9
- Obesity: BMI over 30
Waist Circumference
Measuring waist circumference is an effective method for evaluating abdominal fat, an important indicator of the risk of developing metabolic and cardiovascular diseases. Even with a normal BMI, excessive abdominal fat can increase health risks. The measurement is taken with a measuring tape at the level of the navel. Generally, the risk of developing diseases significantly increases when waist circumference exceeds certain values:
- Men: circumference over 102 cm
- Women: circumference over 88 cm
Body Fat Percentage
Body fat percentage indicates the amount of fat in relation to total body weight. Compared to BMI, this method is more accurate because it also considers muscle mass, bone density, and organs. For example, athletes with high muscle mass may have a similar BMI to someone who is obese, even though their body composition is very different.
There are several methods for measuring body fat percentage, including:
- Skinfold caliper (measuring skinfold thickness)
- Bioelectrical impedance analysis
- Advanced techniques like DEXA scans
In addition to BMI and body fat percentage, there are other tools to determine whether someone is overweight or obese, including waist-to-hip ratio, clinical evaluation, and blood tests.
What Health Problems Can Result from Overweight or Obesity?
Overweight can be the first step toward obesity, a condition that increases the risk of over 40 diseases. Some of the most common include:
- Certain types of cancer: increased susceptibility to cancers such as breast, colorectal, endometrial, kidney, and esophageal cancer.
- Sleep apnea: interruptions in breathing during sleep, with consequences on rest and oxygenation.
- Type 2 diabetes and insulin resistance: difficulty controlling blood sugar, with the risk of cardiovascular, renal, neurological, and ocular complications.
- Hypertension: high blood pressure, which increases the risk of heart disease.
- Heart disease and stroke: excess weight promotes atherosclerosis, increasing the risk of heart attacks and strokes.
- Gallbladder disease: higher likelihood of gallstones and other conditions.
- Osteoarthritis: the added stress on joints accelerates cartilage wear, increasing the risk of osteoarthritis.
Other problems related to obesity include fatty liver, gout, respiratory, dermatological, and mental health issues.
What Are the Causes of Obesity?
Obesity is a complex condition influenced by several factors, including:
- Chemical changes and medications: quitting smoking can lead to weight gain, as can certain medications that alter metabolism.
- Unbalanced diet: excessive calorie intake, large portions, and foods rich in fats and sugars contribute to weight gain.
- Aging: as we age, metabolism slows due to muscle loss and hormonal changes, increasing the risk of obesity.
- Psychological factors: emotions such as stress, sadness, or boredom can lead to overeating.
- Genetics: some people have a genetic predisposition that makes them more likely to accumulate weight.
- Sedentary lifestyle: lack of physical activity reduces calorie expenditure and slows metabolism, contributing to weight gain.
- Sleep deprivation: insufficient sleep alters hormones that regulate appetite and metabolism, increasing the risk of obesity.