82 If the temperature is higher or lower than 20°C, the body must work harder to maintain a stable internal temperature, which can affect basal metabolism. What is the function of the WHO? ONLINE RESOURCES The battle against junk food in US schools to assess: valutare overall: nel complesso WEIGHT AND HEALTH Weight is an important factor for health because it is closely linked to various physical and metabolic processes in the body. Maintaining a healthy weight can help prevent and manage a range of health conditions and improve overall well-being. Basal metabolism Basal metabolism (or basal metabolic rate, BMR) refers to the minimum amount of energy (calories) that a body needs to perform basic, essential functions while at rest (not engaging in physical activity). These functions are necessary for maintaining life and include processes like breathing, circulating blood, regulating body temperature, and supporting brain function. Several factors can affect BMR, including: age: BMR tends to decrease with age, as muscle mass typically decreases and fat mass increases; Liver 19% Heart 8% Kidneys 7% Muscles 20% Digestion 10% Fat 3% Others 16% 158 SCIENCE AND PHYSICS health conditions: illnesses or infections may temporarily increase BMR, as the body requires more energy for immune responses and recovery; diet: severe calorie restriction or malnutrition can lower BMR. <18,5 18,5-24,9 UNDERWEIGHT NORMAL sex: men usually have a higher BMR than women due to differences in muscle mass and hormonal factors; Brain 17% environmental temperature: extreme cold or heat can increase BMR as the body works harder to maintain a stable internal temperature ; genetics: some people are genetically predisposed to have a faster or slower metabolism; hormones: hormones, especially thyroid hormones, play a significant role in regulating metabolism. Conditions like hypothyroidism (underactive thyroid) can lower BMR, while hyperthyroidism (overactive thyroid) can raise it; 25-29,9 30-34,9 OVERWEIGHT OBESE 35< EXTREMELY OBESE Body Mass Index Even though it can vary depending on several factors such as the proportion between fat mass and muscle mass, the Body Mass Index (BMI), which relates height to weight, is used to determine if weight is within the normal range. BMI is calculated using the following formula: BMI = weight (kg) / height (m)² The World Health Organization (WHO) has established the following parameters: underweight: BMI less than 18.5; normal weight: BMI between 18.5 and 24.9; overweight: BMI between 25 and 29.9; obesity: BMI of 30 or higher. These categories help classify weight status and assess the risk of developing health problems associated with being underweight, overweight, or obese.