Have you ever wondered what exactly the word “metabolism” means?

Metabolism is the process by which your body converts what you eat and drink into energy. During this complex biochemical process, calories in food and beverages are combined with oxygen to release the energy your body needs to function. So it basically means “change” and change has to occur for one thing to be transformed into another.

When we are talking about metabolism, the kind of “change” we’re talking about is cellular change – where our bodies turn carbohydrates, protein, and fats into energy.  This process happens in two phases.

Phase 1 is Catabolic: The breaking down of food molecules to be released as energy.

Phase 2 is Anabolic: The building up of molecules for the body to use as needed.

During digestion and metabolism the body is breaking down food (catabolic) so it can build it up again (anabolic) to use as fuel for different functions of the body. These two phases are always working in tandem, meaning they happen at the same time. Catabolism is in the business of releasing the energy that anabolism needs for muscle building, repair, and growth. During physical exercise, both phases are used to exert enough physical energy. This then engages the catabolism factor to burn stored fat after a period of time, which according to some scientific studies, takes around twenty minutes to kick in.

Adenosine Triphosphate (ATP) is an organic compound and hydrotrope that provides energy to drive many complex processes in living cells, e.g. muscle contraction, nerve impulse propagation, condensate dissolution, and chemical synthesis. Found in all known forms of life, ATP is often referred to as the “molecular unit of currency of intracellular energy transfer. When consumed in metabolic processes, it converts either to adenosine diphosphate (ADP) or to adenosine monophosphate (AMP). Other processes regenerate ATP so that the human body recycles its own body weight equivalent in ATP each day. It is also a precursor to DNA and RNA and is used as a coenzyme.

In basic terms, Adenosine triphosphate (ATP) is an energy-carrying molecule found in the cells of all living things. ATP captures the chemical energy obtained from the breakdown of food molecules and releases it to fuel other cellular processes. ATP is also able to power cellular processes by transferring a phosphate group to another molecule through a process called phosphorylation.  This transfer is carried out by special enzymes that couple the release of energy from ATP to cellular activities that require energy. ATP consists of three main structures: the nitrogenous base, adenine, the sugar, ribose, and a chain of three phosphates groups bound to ribose.

Your body consists of approximately fifty trillion cells and within each cell is an estimated one billion ATP molecules that are recycling at a rate of about three per minute. In order for our bodies to stay healthy, ATP needs to be replenished. The body uses nutritious foods and oxygen to replenish ATP. For ATP to burn energy, nutritious foods are the fuel that is required and for ATP to burn energy, the body uses oxygen. The most basic cause of ATP depletion is a lack of oxygen and nutrients which are required Cellular Respiration and glycolysis for the generation of ATP. We can easily diminish ATP by eating bad foods or by food deprivation which can cause inflammation, chronic stress, and hypoxia. Hypoxia is a condition in which the body or a region of the body is deprived of adequate oxygen supply at the tissue level.

Units of energy for carbohydrates, proteins, and fats are either measured in kilocalories (kcal) or kilojoules (kJ). A Calorie is the energy needed to raise the temperature of 1 gram of water through 1 °C (now usually defined as 4.184 joules). One kilocalorie (1 kcal) is equal to 4.184 kilojoules (kJ). To calculate the calorie content, simply divide the kilojoules by calories. Food is calculated by its available energy currency. Once the foods are metabolised in the body, those values are:

• Carbohydrates: 16 kJ per gram
• Proteins: 17 kJ per gram
• Fat: 37 kJ per gram
• Alcohol: 29 kJ per gram

Basal Metabolic Rate (BMR) 

Basal metabolic rate is the number of calories your body needs to accomplish its most basic (basal) life-sustaining functions. The formula calculated a person’s body weight, height, age and gender to determine the total energy expenditure per day in order to maintain weight. One popular way to estimate your BMR is through the Harris-Benedict formula, which takes into account.

Women:

BMR = 655 + (9.6 × weight in kg) + (1.8 × height in cm) – (4.7 × age in years)

Men:

BMR = 66 + (13.7 × weight in kg) + (5 × height in cm) – (6.8 × age in years)

Your BMR can be used to help you gain, lose, or maintain your weight. By knowing how many calories or kilojoules you burn, you can know how many to consume.

If you’ve calculated your BMR using the Harris-Benedict formula, the next step is to include the number of calories you burn during daily activities based on your lifestyle:

• Sedentary. If you get minimal or no exercise, multiply your BMR by 1.2.
• Lightly active. If you exercise lightly one to three days a week, multiply your BMR by 1.375.
• Moderately active. If you exercise moderately three to five days a week, multiply your BMR by 1.55.
• Very active. If you engage in hard exercise six to seven days a week, multiply your BMR by 1.725.
• Extra active. If you engage in very hard exercise six to seven days a week or have a physical job, multiply your BMR by 1.9.

The final number is approximately how many calories you need on a daily basis to maintain your weight. You can then multiply the number of calories by 4.184 to calculate the number of kilojoules you need daily to maintain your weight. This calculation is just an estimate.

Our overall energy expenditure is scientifically broken down into three components:

• Basal Metabolism (BMR): 60-70%
• Thermogenesis (TEF): 5-10% (Thermic effect of food for digesting, absorbing, transporting, and storing)
• Physical activity (PA): 20-35%

Body Mass Index (BMI): 

The BMI equation was formulated to estimate if a person is at a healthy weight for the height by dividing their weight in kilograms (kg) by their height in meters squared. This equation will however not distinguish between muscle, which weighs about 18 percent more than fat nor does it include visceral fat.

To calculate your BMI, divide your weight in kilograms by your height in meters squared.

For example: A person is 1.7 meters tall and weighs 64 kg

Step 1: Multiply the height x 2 (1.7 x 2 = 2.89)

Step 2: Divide the weight in kilograms by the height calculation (64 / 2.89 = 22.14)

BMI = 22.14 which would put them in a normal weight range.

BMI Range: 

• Underweight: <18.5
• Normal: 18.5 – 24.9
• Overweight: 25 – 29.9
• Obese: 30 – 34.9
• Extremely obese: 35<

You can use the BMI calculator above together with the BMR calculator to manage your weight, lose weight, or gain weight.