Nutrition 101: A Guide to Basic Nutrition

Why Starvation “Diets” Don’t Work

Though an individual may lose weight for a period of time while on a starvation diet, the body will eventually respond by retaining fat and slowing the metabolism.

When a person does not ingest enough calories to meet the body’s minium requirements for completing basic metobolic processes (basal metabolic rate), the body will perceive that it is starving and retain fat, its preferred source of energy during times of survival.

Keep in mind that even if you are ingesting enough calories to meet these needs, you must also take into account calories expended during physical activity so that any resulting caloric deficit is not too excessive (never below basal metabolic rate). In addition, during caloric restriction, the body may break down muscle tissue to meet energy requirements (catabolism).

Regular body composition testing will allow you to monitor whether muscle tissue and/or fat are being lost, gained or maintained and will guide you in making appropriate adjustments in activity and daily caloric intake.

The Real Problem With Junk Food

Most whole foods possess the necessary enzymes or the elements to produce the enzymes required in order to digest the host food. Junk food are man made foods that typically do not possess the enzymes or enzyme producing elements to break down the food itself. As such, the body is charged with the task of producing the necessary enzymes (usually in the small intestine) for digestion of the food. The energy and proteins required to produce these enzymes would be better utilized for other biological functions.

Junk foods are often high in calories and typically lack significant biochemical (vitamin) content. These foods often contain saturated fats and trans fats which, due to their contribution to “bad” cholesterol levels and other potential negative health effects, are obviously undesirable.

Understanding Carbohydrates – Simple Or Complex?

Complex carbohydrates are complex chains of sugars which contain soluble fiber. As such, they are absorbed more slowly into the bloodstream. Simple carbohydrates are simple chains od sugars which do not contain soluble fiber and, as such, are more quickly absorbed into the bloodstream. This quick rate of absorbtion causes an over release of insulin from the pancreas. It is the role of insulin to remove excess sugar from the bloodstream for transport to the liver, muscle tissue or adipose (fat) tissue for storage as energy. As the liver and muscle tissue are only able to take up this sugar (in the form of glucose) at a gradual rate, and adipose tissue is able to take it up more rapidly, it is more likely to be stored in fat cells. This potential storage as excess body fat is obviously undesirable.

Complex carbohydrates provide the body with sustained energy during regular daily activity, as well as during exercise. Whole foods such as vegetables, whole grains, legumes and fruit are sources of complex carbohydrates. Table sugar, honey cakes, cookies, and candies are sources of simple carbohydrates.

The Pros Of Protein

Protein is broken down by the body into various amino acids. These amino acids are the basic building blocks for numerous biological processess, including muscle tissue remodeling, hormone synthesis and energy provision. As it is more difficult and time consuming for the body to digest protein, in comparison with other macro nutrients carbohydrates and fat), it is a good source of energy during andurance activity and helps you feel satisfied longer after eating.

Animal sources such as lean meats, fish and dairy products are sources of complete protein (containing all essential amino acids). Plant soruces such as whole grains, vegetables and nuts are typically sources of incomplete protein (containing some essential amino acids).

Use of information or advice in this article is at the sole choice and risk of the user.


E. Howley, B.D. Fitness Professionals Handbook, Fifth Edition, Human Kinetics, 2007

R. Clark, M. Kelly, S. Skinner, C. DeFrancessco, F. Campitelli, NFPT Sports Nutrition Manual, Second Edition, NFPT, 2006

About the Author

Gary Gochenour is a Master Fitness Trainer with the National Federation of Professional Trainers. He can be reached at [email protected].


These resources are for the purpose of personal trainer growth and development through Continuing Education which advances the knowledge of fitness professionals. This article is written for NFPT Certified Personal Trainers to receive Continuing Education Credit (CEC). Please contact NFPT at 800.729.6378 or [email protected] with questions or for more information.