New Year, New you #4 Getting Fat…with Understanding

It is important to understand that not all fat is evil.  The body needs some body fat on it and the diet must have fat it in to support the body. A healthy amount of body fat is necessary to provide protection, temperature regulation, brain function and many other roles for the body.  For men, this between five and fifteen percent of total body weight to be comprised of fat, with women, this range is, before and during the child-bearing years, fifteen to twenty percent.  After menopause women can safely go below fifteen percent if they wish.  Before menopause, a woman with less than 15 percent body fat is potentially at risk for health problems concerning normal menstrual cycles, eating disorders, and osteoporosis. The combination of risk factors is known as the can have extremely negative effects upon the ability to become pregnant or having a healthy pregnancy.  This is especially true for women that are highly physically active and do not consume adequate calories in addition to low body fat levels.  This combination is referred to as the Female Athlete Triad and can have profound negative impact upon a women’s ability to conceive a child.

 The term body fat percent refers to the total percentage of body weight comprised of fat.  Being overweight is defined as having higher than 20% body fat while being obese is defined as having higher than 30% body fat.  Compared with people with healthy body fat levels, people who are overweight or obese are far more likely to have health problems like heart disease, high blood pressure, high cholesterol, diabetes, joint replacement, acid reflux disease and many other problems.

How the body uses food

Each pound of body fat stores the equivalent of approximately 3500 calories worth of energy.  It is important to understand that all of this potential energy is not the body’s first choice of energy to support life or exercise.  To better explain this, a basic understanding of how the body digests and uses energy from food is necessary.  All food, when digested enters the blood stream, from the intestines, as blood glucose.  Blood glucose does three things: it either becomes stored in the muscles as muscle glycogen to provide energy for physical activity, or it remains in the blood stream, as blood glucose, circulating to meet the chemical and biological needs of the body.  Finally, all blood glucose that can not immediately be used for the first two roles is stored as body fat.  For most people, it does not take much food to meet the first two needs.

The Basics: why fat is hard to lose

Before the body can use stored body fat for energy it must first must use all muscle glycogen and blood glucose, circulating in the blood, before it will breakdown body fat for energy.  For this reason, it is practically impossible to lose body fat without exercise.

When the body is exercising, it finds its support for energy in the following order.

•      Muscle glycogen is used first

•      Then blood glucose is used

•      When circulating blood glucose is gone, it is replenished from the liver

•      When the liver runs out of glucose then body fat is broken down for energy

•              This process is much slower. This is typically the point where a person feels that they have “hit the wall”

It is for this reason, therefore, that intensity of exercise is more important than duration because the body must burn through all the stored forms of glucose before body fat is broken down.  So how much work must be done?  Within the muscles, about 300-400 grams or 1200-1600 calories of muscle glycogen, stored throughout the body.  For the most part, these calories are really only used during exercise.

 An additional 70-110 grams or 280-440 calories are circulating in the blood and stored in the liver, the body is constantly using and replenishing this supply to perform functions such as breathing, heart rate, digestions, and many other chemical processes.   These activities are constantly going twenty-four hours a day, every day of your life.  The nice thing about this is that when the blood glucose levels are low the body tends to breakdown body fat to replenish these levels of 280—440 calories.  The problem is that even for someone who consumes a healthy diet specific to that person’s individual calories needs; the blood sugar levels never go low enough to lose significant amounts of body fat.

On the flip side, let’s say that a person exercises incredibly hard and burns 700 calories in an hour long workout (most people only workout hard enough to burn about half of that in an hour).   The body naturally wants to replenish that 700 calories burned from the muscle glycogen and begin the recovery process.  The body begins this process immediately by drawing from the blood glucose until it is depleted and then, restoring blood glucose levels by breaking down body fat.  But to rely on this exclusively for weight loss requires constant exercise at an incredibly high intensity, almost every day until the goal is achieved.  For most people this is not practical in everyday life, much less appealing.  It is for this reason that a combination of diet and exercise is the quickest way to burn through this and start melting body fat.  Also, this is why intensity of exercise is far more important than duration.

To this point, we have looked at a very basic overview of what the body goes through when exercising.  The process is far more complicated than I have described here in this simple explanation.  Please note, that nutrition is a very important part of recovering from exercise, and that based upon this explanation for calorie usage and body fat breakdown, I am NOT suggesting avoiding eating after exercise.  Post-exercise nutrition is a very necessary and fundamental component of weight loss.  The details of how to properly do this will be discussed in a later chapter.

Dietary Fat

Most of the time a person does not need more than 30% of the daily calories to come from fat and minimum of 10% is necessary to avoid health problems.  Fats, like all calories, are a source of energy, with one gram of fat being equal to nine calories. Fats serve and important role in controlling satiety, the feeling of being full.  They help a person feel fuller, longer than carbohydrates will and fats give food flavoring.

Dietary fat can carry essential nutrients. Essential nutrients are those that must be consumed through a proper diet because the body does not produce enough of it on its own.  In the blood stream dietary fat is transported as glycerides or cholesterol depending upon the source of the fat. There are eight things to know about dietary fat:

1.      Fats and oils: fats are solid at room temperature and usually are high in saturated fat content. Oils are liquid at room temperature and typically contain unsaturated fats

2.      Triglycerides, diglycerides, and monoglycerides

•      Triglycerides are the most common form of dietary fat and oils

3.      Fats can be classified as short-chain, medium-chain, and long-chain fats.  Long-chain fats the most common. 

4.      Polyunsaturated fats: have the tendancy to lower blood cholesterol, both LDL and HDL.  These are healthy fats and are found in vegetable and cereal oils

5.      Monounsaturated fats: These fats lower LDL cholesterol while keeping HDL cholesterol levels up.  These are the healthiest fats.

6.      Saturated Fats: raise cholesterol levels, less healthy than unsaturated fats, found in meat and dairy products.  As well as anything that has been fried in crisco, lard, or grease.

7.      Low-density lipoproteins (LDL):  these are the major carrier of cholesterol and other forms of lipids (fats) in the blood stream.  They try to keep fats in the body

8.      High Density Lipoproteins (HDL): These lipoproteins carry fats away from storage and to the liver for metabolism into something useful or elimination from the body

Healthy people have low LDL cholesterol numbers and HIGH HDL cholesterol numbers

Healthy sources of saturated fats

•      Eggs

•      Chicken

•      Turkey

•      Fish

•      Lean ground beef (85/15 or better)

•      Bison

•      Wild Game

Healthy sources of unsaturated fats

•      Olives

•      Olive oil

•      Avocados

•      Nuts

•      Salmon