Calories are a unit of measurement that quantifies the energy content in foods and beverages. They represent the energy the body can obtain from consuming a specific food or drink, essential for fueling all bodily functions, from breathing to physical activity. Caloric intake and expenditure are central to maintaining, gaining, or losing weight, and they play a significant role in overall health and metabolism.
Overview:
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Energy Source: Calories provide the energy required for daily activities and bodily functions, such as breathing, circulation, digestion, and exercise. Macronutrients—carbohydrates, proteins, and fats—are the primary sources of calories, with each offering a different amount of energy per gram:
- Carbohydrates: 4 calories per gram
- Proteins: 4 calories per gram
- Fats: 9 calories per gram
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Basal Metabolic Rate (BMR): This is the number of calories your body needs at rest to maintain basic physiological functions. It varies based on factors like age, gender, weight, and muscle mass.
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Caloric Balance: Caloric intake must balance with caloric expenditure to maintain weight. Consuming more calories than burned leads to weight gain, while consuming fewer can lead to weight loss.
Importance in Nutrition:
- Nutrient Density: Calories alone don’t determine the healthfulness of food; nutrient-dense foods provide vitamins, minerals, and other nutrients in addition to calories.
- Supplements and Calories: Some dietary supplements are low-calorie options that support nutrient intake without adding significant calories, making them beneficial for those monitoring their caloric intake.