Our body requires energy for its metabolism and physical functions. It derives energy from food and its macronutrient components, ie carbohydrates, fats, and proteins. Dietary energy intake from food should meet the requirements for the attainment and maintenance of optimal health, physical work and well-being.
Energy requirement is the amount of food energy required to maintain the level of physical activity required to suit body size, body composition, and long-term good health. Dietary energy needs cannot be considered in isolation of other nutrients in the diet, as the lack of one will affect the others. Thus, energy requirements must be met through the consumption of a diet that meets the needs of all nutrients.
Mitochondria are found in the cytoplasm of all eukaryotic cells, namely, cells with clearly defined nuclei. Their primary function is to generate large amounts of energy in the form of adenosine triphosphate (ATP). The number of mitochondria per cell varies widely.
ATP, an energy-carrying molecule, is found in cells of all living things. When ATP breaks down, energy is released and can be harnessed for cellular work. Because ATP breaks down and reforms so easily, ATP is like a rechargeable battery that powers cellular processes.
ATP is often referred to as the “molecular unit of currency” of intracellular energy transfer. ATP captures the energy gained from the breakdown of food and releases it to fuel cellular processes. Our body rebuilds and recreates its body weight equal to ATP each day.
Daily energy requirements –
There is a very small amount of ATP in the body. Therefore, it is necessary to have sufficient energy reserves for backup. The amount of daily energy requirement depends on a person’s daily energy consumption and metabolic energy requirement, which depends on one’s body weight and level of activity.
In order to fuel our body, the energy we get from food is measured in kilojoules. Fats, carbohydrates and proteins, which are found in foods, all provide energy.
The basic energy consumption of the human body is 4 kilograms per kilogram of body weight per hour. So a person’s basic energy consumption can be calculated as follows:
Total energy consumption = body weight (kg) × 4 KJ × 24 hours / day / 4.18 kJ
The total energy consumption value is divided by 4.18 kJ so that the value can be converted to kilocalories (1 kcal = 4.18 kJ). This calculation represents daily energy consumption.
Different energy requirements vary with age, sex, body size, and activity level. Excess food intake that is not used as energy can be stored as body fat. Excessive fat storage can lead to a high body mass index (BMI).
BMI indicates a person’s body fat and is determined by a person’s height and weight. In adults, the commonly suggested BMI is between 19 and 24. High BMI can potentially cause illness or health complications. To have an ideal BMI, a person’s energy intake should not exceed the energy burned regularly.
Energy balance –
Energy balance is the relationship between the calories taken in the body through food and drink and the calories being used in the body for our daily energy needs.
When you take more calories than you consume, you are in a positive energy balance. When you take fewer calories than you consume, you are in a negative energy balance. You energy balance affects your metabolism, hormonal balance and mood.
A negative energy balance leads to weight loss. The body detects an energy deficiency and the fat stores are said to make a difference. A positive energy balance has its own implications not only in terms of weight gain but also in terms of health and fitness.
The conclusion –
Our body’s metabolic and physiological functions require energy, which arises from the food we eat. The mitochondria that are found in the cytoplasm of all eukaryotic cells generate large amounts of energy in the form of ATP. Our body generates the equivalent of its body weight in ATP each day. Personal energy requirements vary with age, gender, body size, and level of activity.