Carbs, Proteins, and Fats...But What About Fiber

Fats, proteins, and carbohydrates are all digested at a different pace and each one has unique components that are used by the body in different ways.

CARBOHYDRATES

Carbohydrates or “carbs” begin the digestion process in the mouth.  Salivary enzymes begin to break down the simpler sugars.  The process of chewing helps to break down these foods further.  As carbs pass through the esophagus and stomach, digestive enzymes continue to break down the simpler sugars even further (Dietary Reference).  Once carbohydrates reach the small intestine, the final digestion takes place.  They are broken down into the simplest form of sugar and absorbed through the walls of the small intestine into the blood stream (Dietary Reference).  The body either uses the glucose absorbed right away or stores it in the liver for use at a later time.

PROTEINS

Proteins are the building blocks of life.  Protein is found in meat, eggs, dairy products and legumes (beans).  Protein molecules are quite large.  Chewing, taking place in the mouth, begins the process of digestion.  It breaks down the protein into smaller particles.  Chemical digestion starts in the stomach (Dietary Reference).  Enzymes found in the stomach acid start to soften the protein molecules.  More enzymes are released from the pancreas once the protein reaches the small intestine.  This completes the digestion process.  Proteins are broken down into amino acids in the small intestine (Dietary Reference).  Amino acids are absorbed into the blood stream.  From here, they travel throughout the body to repair injuries to tissues and replace dying cells.

FATS

Fats and oils are not easily digested.  They do not mix with the watery digestive juices in the esophagus and stomach.  Bile, which is produced in the liver and secreted by the gall bladder, attaches to fats (Dietary Reference).  Bile breaks up clumps of fat into smaller particles in the small intestine (Dietary Reference).  Lipase, a fat digesting enzyme, is released.  The broken down fat particles, cholesterol and fatty acids, accumulate in the veins and then are carried to fat-deposit areas to be stored and used for fuel for the body later (Dietary Reference).

GOOD FATS VS. BAD FATS

There are basically two types of fat:  saturated and unsaturated.  The unsaturated fats are considered the “good guys”.  These include polyunsaturated fatty acids and monounsaturated fatty acids (Dietary Reference).  Both of these types can help lower cholesterol levels and reduce cardiovascular risks.  Poly fats, found mostly in plant products or vegetable oils, can be used to replace saturated fats in baking and cooking (Dietary Reference).  These help to lower triglycerides and cholesterol levels.  One especially beneficial type of polyunsaturated fats are omega-3 fatty acids.  This type of fat is found in fatty fish such as salmon.

The “bad fats” should be eaten sparingly.  These contain saturated fats and trans fatty acids.  Both of these types have been proven to clog arteries, raise cholesterol levels and increase the risk for heart disease (Dietary Reference).  These types of fats are typically found in animal products or in the hydrogenation process of food processing.  These are called added fats.

WHAT ABOUT FIBER

Dietary fiber, found mostly in fruits and vegetables, whole grains and legumes.  Fiber includes all parts of the plant foods that your body can’t digest or absorb.  It passes relatively intact through your stomach, small intestine, colon, and out of your body as waste (Dietary Reference).  Fiber comes in two forms, soluble and insoluble.  Soluble fiber dissolves in water to form a gel like material (Dietary Reference).  It can help lower cholesterol and blood glucose levels.  Soluble fiber can be found in oats, peas, beans, apples, and citrus fruits.  Insoluble fiber helps the movement of material through the digestive tract and increases stool bulk.  It helps with constipation (Dietary Reference).  Most plant based foods contain both forms of fiber.  The benefits of a high fiber diet include:  normalizes bowel movements, helps maintain bowel health, lowers cholesterol levels, helps control blood sugar levels, and aids in achieving a healthy weight.

Dietary Reference Intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids (macronutrients). Institute of Medicine. http://www.nap.edu/.