Carbohydrates are perhaps one of the least understood aspects of nutrition in our modern diet. We’ve all heard of the no-carb or low-carb diets. We’ve all heard carbs are bad. The same as all the Fad diets: low fat, sugar-free, gluten-free, low sodium, and whatever other fancy name you want to give it or have read about. It’s not quantity but quality.
The fact of the matter is we need carbohydrates for energy, to feed our brain, and for the proper use of protein. We just don’t need most of the carbohydrates that are available in our current culture. So, it’s important to learn to tell the difference between good carbohydrates and bad carbohydrates and understand how the human body metabolizes them.
There are complex and simple carbohydrates. The more complex a carbohydrate is, the longer it takes to digest and enter the bloodstream. The simpler a carbohydrate is, the faster it enters the blood stream and causes spikes in blood sugar levels.
We often think of sugars and starches as carbohydrates, but seldom do we consider plant foods as carbohydrates. It is these plant foods that are the most important ones, the “good carbohydrates.”
Types of Carbohydrates
Carbohydrates are basically broken down into 3 types.
Monosaccharides
Single Chain sugar, the simplest of carbohydrates. These are digested very rapidly.
Glucose: This is the form of sugar found in the human blood stream and is used by the body for energy. All carbohydrates must be broken down into this form for the body to use it. It is found naturally in Honey, fruits, and Sweet Corn. It is chemically produced by Dextrose, Corn syrup, and other processed simple sugars.
Fructose: Found naturally in fruits and honey. This is also chemically produced in processed sugars such as high fructose corn syrup.
Galactose: is produced from the breakdown of milk sugar (lactose).
Disaccharides
Double chain sugars which are also digested quickly.
Sucrose: Formed when glucose and fructose are bonded together. This includes table sugar, sugar beets, molasses, and maple syrup.
Lactose: Formed by the combination of glucose and galactose. This is the sugar that is found in milk and dairy products.
Maltose: Formed by two units of glucose bonded together. This is caused from the breakdown of starches and occurs in germinating seeds.
Polysaccharides
Made up of complex multi-chain sugars. These take longer to digest and aid in digestion and elimination.
Starches: Made up of many (often hundreds) of glucose units. These are found in whole grains, roots, vegetables, and legumes. It requires chewing and enzymes to be digested, and in some cases (like grains and legumes) must be cooked first.
Glycogen: Formed by Glycogenesis when the body has excess glucose in the blood stream that is not needed for energy. The pancreas releases insulin which then activates conversion into glycogen by the liver and the muscles. It is stored there until it can be used as energy (muscles) or converted back into glucose (liver) and used by the body. If there is more glycogen than can be stored in the liver and muscles, it is converted into fat.
Cellulose: Made up of several glucose molecules and is the “skeleton” of plants. It is what gives plants their strength and supportive structure. It is an indigestible plant fiber, yet is important in proper elimination and preventing stagnation and build up in the colon.
Hemicelluloses: Another type of indigestible plant fiber that absorbs water and forms a gel, which gives a laxative effect. These include Pectin (found in ripe fruit) and agar-agar (found in seaweed).
Fiber: Found only in plant foods and is not digestible by the human body. There are two kinds, and it is important to have both every day for proper digestion and regulation. Soluble fiber helps to lower cholesterol and blood sugar and can be found in fruits and vegetables such as apples, persimmons, carrots, turnips, plums, nectarines, and squash. It can also be found in legumes, oats, and barley. Insoluble fiber is found in all fruits and vegetables and whole grains. It helps keep the digestive system running smoothly and efficiently, prevents constipation and other digestive problems.
How Does the Body Digest Carbohydrates?
It all begins in the mouth by chewing. An enzyme is released called amylase that begins to break down carbohydrates. Food then moves into the stomach which slows or stops this process due to the stomach acids. Once it enters the small intestine another amylase enzyme is secreted by the pancreas and continues to break down the carbohydrates into simpler sugars.
As it continues through the intestines, it is broken down into glucose and is absorbed through the intestinal walls into the bloodstream. At this point it is either used by the body for energy, for regulating nerve and brain function, or it is converted into glycogen and stored in the liver and muscles, or stored as fat.
Without adequate good carbohydrates in the daily diet, our body is forced to use protein for the production of energy. If this happens, protein cannot be used for building, repairing, and maintaining body tissues and cell production. In addition, the human body has a tendency to have increased risks for pathogenic diseases and most digestive disorders.
Eating simple sugars like sweets, breads, processed grains, excessive amounts of dairy and junk food are bad carbohydrates. These are quickly converted to glucose causing spikes in the blood sugar, feeding pathogenic yeasts and microbes in the digestive tract, lowering your immune system, and increasing your chances of diabetes, cancer, and heart disease.
Carbohydrates are crucial for good health, so long as you are consuming adequate amounts of GOOD carbohydrates. Vegetables should be your main source of carbohydrates. Small amounts of low glycemic fruits are also acceptable. Instead of snacking on candy, chips, and junk food, try grabbing some veggies or an apple. Once you get over the sugar addiction, you won’t crave the junk anymore; you’ll crave the good stuff!
What is the Glycemic Index?
The Glycemic Index is a system that was developed to rank foods based on how they affect blood sugar levels within 2-3 hours after eating. The idea is that simpler carbohydrates cause spikes in blood sugar almost immediately forcing the pancreas to release insulin and increasing problems with diabetes. Complex carbohydrates are digested slower and release glucose into the blood stream at a slower pace allowing your body to use it as energy rather than forcing it to convert it into glycogen.
The Glycemic Index can be confusing, however, because there is also something called Glycemic Load. Glycemic Load takes into account the amount of available carbohydrates. What this boils down to is there may be a food with a high GI but a low GL which means it does not cause spikes in the blood sugar and is more readily used by the body. So, while the Glycemic Index is a good basis to work from, it is not the end all rule to go by.
Most importantly, eating a wide range of vegetables, especially leafy greens and high fiber vegetables is the way to go. The more colors, shapes, and sizes you can include in your daily and weekly diet, the better. Avoid simple processed carbs like bread, sugar, white rice, etc…and you will be fine.
To understand more on the glycemic index, please go to Mendosa.com. He has provided an Advanced Glycemic Load Data in excel format that is invaluable. He continues to update it as new information becomes available, and it is a great way to understand the comparison between the Glycemic Index, the Glycemic Load, and what foods are best to eat.
There are good carbs and bad carbs.
Learn to know the difference.