Metabolism is the aggregate of all chemical processes that take place in living organisms, resulting in growth, generation of energy, elimination of wastes, and other body functions as they relate to the distribution of nutrients in the blood after digestion. Metabolism takes place is two steps: anabolism, the constructive phase, in which smaller molecules (such as amino acids) are converted to larger molecules (such as proteins); and catabolism, the destructive phase, in which larger molecules (such as glycogen) are converted into smaller molecules (such as glucose). Exercise, elevated body temperature, hormonal activity, and digestion can increase the metabolic rate, which is the rate determined when a person is at complete rest, physically and mentally. The metabolic rate is customarily expressed (in calories) as the heat liberated in the course of metabolism.

Basal Metabolic Rate
Living tissue is maintained by the constant expenditure of energy. The body's energy requirements must be met by the caloric value of food. The total rate of body metabolism, or the metabolic rate, can be measured by the amount of heat generated by the body or by the amount of oxygen consumed by the body per minute. This rate is influenced by a variety of factors, including physical activity, eating, body temperature, and by the effective or ineffective function of the bodies organs. The increased rate of metabolism that accompanies eating can last more than six hours. Below you will find the basal metabolic rate and daily caloric needs of our three group members.

Jennifer: BMR of 1684.8 with a Daily Calorie Need of 2316.6 per day.
Joelle: BMR 1517.25 of with a Daily Calorie Need of 2086 per day.
Sandra: BMR of 1584.25 with a Daily Calorie Need of 2178 per day.
Check it out! To find your own BMR (basal metabolic rate) and Daily Calorie Needs by going to the following links: and

In general, individual differences in energy requirements are due primarily to differences in physical activity. A person who is sedentary will have a lower BMR, than a person with an active lifestyle. When caloric intake is greater than the energy expenditures, excess calories are stored as fat, regardless of the source of the calories (i.e. carbohydrates, proteins, fats). As nurses we will be educating patients about nutrition and weight. One thing that we see commonly is obesity and knowing how metabolism affects health and weight loss is tremendously important. Our primary goal is to teach the patient on how to increase his/her BMR and to control the amount of calories ingested daily. Caloric intake needs to be less than the energy used for a patient to lose weight. The safest and most effective way to achieve weight loss would be to increase physical activity while reducing the calories you take in. It is essential to remember that the more active you are, the more energy you need, the higher your BMR!

The Role of Enzymes in Metabolism

Enzymes make certain chemical reactions that are essential for life work faster. Enzymes catalyze the chemical reactions necessary for metabolism and without them, these reactions would happen too slowly to sustain life. They do this by reduces the amount of free activation energy which reduces the amount of energy needed to initiate a reaction. As you can see by the figure below, there are numerous enzymes with complex functions.



Essential Question #1
In researching products that claim to boost metabolism, the most interesting product I found is Homeopathic hCG (human chorionic gonadotrophin) hormone along with a VLCD (Very Low Calorie Diet). hCG is a hormone produced by the placenta during pregnancy. According to Dr. Simeons' book, Pounds and Inches, a course of hCG along with a very specific 500 calorie diet will burn the stubborn abnormal fat accumulations in the body without affecting the structural fat (fat that cushions, protects and supports organs). The only 'product' that you take is the hCG hormone. According to the above mentioned book and the people who have followed this diet, weight loss is rapid and permanent. The hCG boosts the metabolic rate and because the diet does not allow fats or starches, the body begins to use up the accumulated fat in the body. The following video highlights the key points of this diet.

Essential Question #2
Crash diets are a common fad. People have tried to eat nothing but grapefruits, cabbage, or other foods all in the hopes of accelerated weight loss. Because these diets cause the body to go into starvation mode, metabolism is actually slowed to preserve as much of the existing available nutrients and fats. Then after the person begins to eat normally again, the metabolism is still decreased and the body stores more fat to keep on reserve. This causes rapid weight gain (usually significantly more than was lost during the crash diet). It is very difficult to restore the pre-diet metabolism rate.

One thing we did not cover regarding metabolism is the effect of hormones on metabolism. Hormones are just as important as enzymes. A lack of or an overabundance of any hormone will cause serious disorders of metabolism. Diabetes Mellitus is a great example of this! If the pancreas does not produce and secrete enough of the hormone insulin the body is unable to metabolize sugar. A high level of glucose in the blood can be life threatening. Hypothyroidism is another great example. If the thyroid gland does not produce and secrete enough of the hormone T4 or T3 all of the bodies processes are drastically slowed. This often leads to obesity, fatigue, dry skin, and much more. Metabolism sustains life and there are many factors that determine the level of metabolism in our bodies. All of our organ systems need to function properly and work together for homeostasis and thus, metabolism to enjoy healthy lives. Eat right, be physically active, and enjoy life!

rapid weight loss
Mosby's Dictionary of Medicine, Nursing, & Health Professions, 8th Edition
Fox, Stuart Ira. Human Physiology, 10th Edition. Chapter 19 Regulation of Metabolism
Simeons, A.T.W. Dr. Pounds and Inches