METABOLISM
We need energy for every activity. For us to move from one place to another, we need to use our muscles and bones. As the muscles contract and relax, we are able to use our hands and feet. We get heat to keep our bodies warm from food. This heat is released from food as they are broken down. We also get warm from activities such as walking and running.
Definition of Terms
Metabolism: The chemical processes that go on in our bodies are referred to as metabolism. Even when we are resting or sleeping, the chemical activities still go on to keep us alive. Wardlaw and Insel (1995) sum this up by saying that metabolism refers to all the chemical processes involved in maintaining the body.
Anabolism: Some of the chemical processes end up with the building up of compounds and they are referred to as anabolic processes. A good example is the building up of carbohydrates from photosynthesis.
Catabolism: In some of the chemical processes, compounds are broken down. An example is tissue respiration, by which glucose is broken down to release energy.
Basal Metabolism: It is the cellular activity required to maintain life. Your basal metabolism refers to all the automatic functions of your body. These include breathing, tissue repair, blood circulation and growth. The amount of energy your body uses when you are at rest. Basal metabolism is actually a term used to describe the biochemical changes which take place while you are at rest, lying down, still, relaxed and warm. It is also called resting metabolism.
Basal Metabolic Rate: The amount of energy used up within a specified time is the Basal Metabolic Rate (BMR).
Measurement of Energy
The amount of energy produced when the body breaks down the ‘fuel’ from food is measured in joules. Originally the term ‘calories’ was used and so you will still see ‘calories’ in a lot of books.All foods have their energy values. The food belonging to the class of – Fats and Oils has the highest energy values. Thus, all foods that have fats such as bacon, pork, mayonnaise, butter, vegetable oils, milk from the class of animal and animal products have very high energy values. The other groups that have high energy values are the cereals starchy roots and plantain and the nuts and legumes.
Vegetables on the whole have low energy values. Examples of the energy value of foods some foods are butter (3,122 KJ), mayonnaise (3,001 KJ), melon (96 KJ).
Factors Affecting Basal Metabolic Rate
The amount of energy used up for basal metabolism differs for different individuals. Other people may have smaller food needs because their basal metabolisms are lower.
The type of activity also affects metabolism. The body uses more energy after a rigorous exercise. This shows that the more you indulge in exercises, the higher your metabolism and the more energy you use.
Other factors include age, gender, and the percentage of body lean mass. BMR is known to decrease with increasing age. Our mass of lean tissue is in turn influenced by gender and physical activity. Since males are generally known to have higher activity levels, their BMR tends to be higher.
ENERGY UTILIZATION AND BODY WEIGHT
The type of food gives us different amounts of energy levels. To maintain the ideal body weight, the amount of energy we get from the food we eat must equal the amount of energy we burn out. For example, if we exercise more then we should equally eat more to replace the burnt out fuel. The important actions in maintaining our body weights are exercise and discipline in our eating habits.
Micronutrients Overview, Food Sources and Functions
Energy Balance
Energy balance of our bodies is achieved when the intake of energy exactly equals the energy expenditure. These activities include the basal needs, voluntary physical activities, digestion and absorption.
If the amount of energy intake is less than what the body spends then the result is negative energy balance. On the other hand, if the energy intake is more than the amount spent, positive energy balance results. Guess what will follow in these two instances and write them in your jotters for the next face to face session.
Importance and Measurement of Energy Balance
The body weight depends on negative and positive energy balance. Negative energy balance will bring about weight loss, while positive energy balance will bring about weight gain. When the body stores excess fat the person can be overweight. When the body weight exceeds 20% of normal weight for height the person can be described as obese.
Measuring your body fat in percentage is a better way of measuring energy balance. One way by which you can measure skinfold thickness using a calibrated caliper. You can also use the Body Mass Index (BMI) to measure your body fat level to find out whether there is any health risk.
You can calculate your own BMI by dividing your weight in kilograms by your height in metres squared or you can use tables. BMI of 25 is a low health risk. Any BMI figure exceeding 25 represents high health risk, while 40 is very high.
Genetics determines our body type but environmental factors can change what nature has provided.
Disorders of Energy Balance
Eating disorders are conscious behaviours that produce in energy balance, resulting in obesity or emaciation. There are often disorders ranging from eating too much or refusing to eat. The most common eating disorders include: obesity (body weight 20% or more above normal for height), bulimia (purge disorder) and anorexia nervosa (self-imposed starvation).
If your present eating habits have resulted in your becoming under weight or overweight, then you need to take action to correct the situation.
If you are overweight then you must note these suggestions so that you can lose weight.
- Exercise daily. Exercise will make your body fit and help you to deal with stress.
- Dieting does not mean skipping meals. What it means is that you want to control your food intake for a specific purpose. The weight-loss can be achieved effectively if you cut down on the amount of calories (energy foods) you take in. The foods you eat must give you a total of energy below the calories that your body uses.
- To cut down on the calorie-intake avoid the intake of high calorie snacks. Do you take a lot of meat pies/ turnovers, cakes, chips and soft drinks? If you do then it is time to reconsider your habit if you are losing weight or you intend to. Use more fresh fruits for snacks.
- Your body needs all the nutrients. This is a fact so even when you are eating less food. For example, eat lean meat. Avoid red meat and fatty foods.
- If you are losing weight, try to do it slowly. This way, a habit will be built up. If you adopt the crash weight-loss programme, you may go back to your original poor habits. You may also develop some dangerous side effects.
Suggestions for Individuals who want to gain weight.
- Exercise regularly.
- Plan your meals around favorite foods but eat more frequently.
- Eat larger portions of food.
- Snack on high-calorie, fresh nutritious foods such as nuts whole-grain cereals, milk and ice-cream if you can afford it.
- Think of other parts of your life-lifestyle. Check if you are getting enough sleep. Check if you are not involved in too many strenuous activities. Are you often stressed up? If you are then slow down. Take adequate rest. Eat well.
- Be patient. Do not undertake any rapid weight gain.
- Avoid the use of drugs. These drugs can affect your health later on in life.
Summary
Metabolism has two aspects, which are the building up process and the breakdown process, i.e. anabolism and catabolism. Even when the body is at rest it still uses energy for various activities including the heart beat. The usable fuel energy is known as Adenosine Triphosphate (ATP).
The basal metabolic rate is the amount of energy used up when the body is at rest. When one wakes up and starts walking, the amount increases. Different people use the energy in different amounts. Metabolism refers to the breakdown or builds up processes in the body of an organism. It is affected by the type of activity. After a rigorous exercise, the body uses more energy. The basal metabolism is low when the body is at rest.
Energy balance and exercising and disciplining eating habits will help in maintaining the body weights. The food we eat provides energy. It is very important to identify and measure energy balance since this will help find out if one is in good health or not so that the necessary steps can be taken to correct it.
Excessive and long periods of weight gain results in obesity leading to hypertension,
diabetes, heart problems and oedema in some severe cases.
Vegetarian diets. You should be in a position to help any person who wants to be a vegetarian.
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