Have you ever seen a fat cheetah?

To be fast you must be thin. Cheetahs, the fastest animals on earth, can reach speeds of 70 MPH, but only because they are so skinny. The same principle applies to humans. It is easy to see that the athletes who win races are very thin.

In general, for a given muscle power and leg speed, the lighter the load, the faster the speed. Athletes with a higher percentage of body fat will run slower than they could run if they were leaner. But how do you get thinner?

There are many different opinions on this topic, some are not helpful, some are even dangerous. The following review of some dietary data and new research reveals sensible and safe ways for an athlete to become leaner and stronger.

First, some basic food facts:

There are three basic food groups:

1) Proteins build muscles, organs, bones, enzymes, immune cells, and many hormones.

2) Carbohydrates are fuel for immediate use.

3) Fats provide insulation, buffering, and calorie storage and help form cell membranes and some hormones.

All foods can turn into fat if eaten in excess. Excess carbohydrates, proteins, and fats will make you fat. A little known fact is that most of the protein we eat is converted to carbohydrates and used for fuel or stored as fat. For example, 83% of the whey and soy proteins that are consumed are not used to form body proteins, but as carbohydrates.

This is why:

Protein in food is made up of amino acids joined like beads in a chain. When a protein food source is digested, amino acids are released and absorbed in the small intestine. Some of these amino acids can be used as building blocks that are recombined to build the proteins needed by the body. Only amino acids that are available in the correct proportions can be used to build body proteins.

How much of the protein that is digested and absorbed is used to build body proteins?

That depends on the protein source. Most people think that if they eat 30 grams of protein, their body will use all of those 30 grams to make new proteins or to replace proteins that are naturally lost each day. In reality, this is not what happens.

Each protein source is made up of different amounts of individual amino acids. Each protein source has a different percentage of its amino acids that can be used to build body proteins.

A chicken breast (raw, boneless, and skinless) has about 23 percent protein. Therefore, 3 oz (85 g) of chicken breast would contain approximately 19.5 grams of protein. (In a healthy individual, about 2-8% of the protein is indigestible, leaving at least 18 grams of digestible protein.) What is important to note is that of these 18 grams, only about 30% (about 5 grams) is actually “used” by our bodies to make or synthesize new proteins. The rest (about 13 grams) is broken down and becomes a source of calories.

If you look at whey protein, only 16% of the amino acids are used to build protein in the body. Therefore, 84% of the amino acids are not used to make protein and simply become a source of additional calories.

It is also important to understand that if amino acids are not utilized in a protein source or amino acid formula, in addition to releasing calories, harmful nitrogen wastes are released that must be eliminated by the body. (Excess nitrogen waste can stress the liver and kidneys, especially as we age.)

Although all the food groups (fats, proteins and carbohydrates) can be used as an energy source, only proteins can provide the essential amino acids necessary to form proteins in the body. (Carbohydrates are the body’s preferred source of energy.)

So how do you get a slim body?

First. Use carbohydrates wisely. Except during intense training, avoid products that contain high fructose corn syrup. Instead of consuming sports bars and beverages with high fructose corn syrup, eat natural and unprocessed foods, including starchy fruits and vegetables.

Second. Avoid all refined grains (white flour, white rice, and most baked goods). They are a bad source of food for everyone.

Third. Avoid most processed foods and “fast” foods. Read food’s labels. If additives, preservatives, colorants, chemicals, flavorings, seasonings, etc. are listed, let them go.

Four. Avoid all foods with trans fat, fried foods, and margarine.

In general, eat mostly healthy, natural, and unprocessed foods: fruits, vegetables, fish, nuts, unprocessed meats, beans, and eggs. Eat like our caveman ancestors. (Eliminate sugar and processed foods).