Carbohydrates are essentially sugar that come in different forms such as simple sugars, starches and fiber. Though they have other functions, the main job of carbohydrates is to provide energy. Carbohydrates come in all shapes and sizes and though most people think of bread and pasta as the main source of carbs, it’s important to remember that most people, like 99.9%, can get all of the carbs they need through whole fruits and vegetables. Carbohydrates are broken down into simple and complex, the difference being how many sugar molecules they contain. Simple sugars only contain 1-2 sugar molecules which means they can be broken down and absorbed very quickly. Complex carbohydrates have 3 or more sugar molecules so they take longer to digest.
Simple Sugars
Simple sugars are divided into monosaccharides, meaning they only contain one sugar molecule, and disaccharides, which contain 2 sugar molecules. Monosaccharides can’t be broken down any further and so can be absorbed into the bloodstream quickly, except for fructose (see next weeks blog on Fructose…Friend or Foe?). There are 3 types of monosaccharides: glucose, fructose which is the primary sugar found in fruit, and galactose which is the primary sugar found in dairy products
Disaccharides are made up of 2 monosaccharides. The bond between the 2 molecules has to be broken down before the sugar molecules can be absorbed. There are primarily 3 types of disaccharides: sucrose (glucose + fructose),or table sugar which is derived from sugarcane or sugar beets. Lactose (glucose + galactose), the sugar that is found in milk, and maltose (glucose + glucose), which is found in malt beverages such as beer and malt liquor.
Complex Carbohydrates
Complex carbohydrates are made up of sugar molecules that are linked together to form long, complex chains. They are typically found in peas, beans, whole grains and vegetables. Because of the complexity of these carbs, they take longer to digest and don’t spike your blood as high as simple sugars. Complex carbohydrates are divided into starch and fiber.
Starch
Starch is made by plants and is made up of chains of glucose. It is soluble in water and is typically used as a thickening agent in many processed foods because it is tasteless and odorless. The 4 major resources of starch in the US are corn, potatoes, rice and wheat. Starch that is absorbed from the small intestine will raise your blood sugar. However, some starch doesn’t get absorbed and continues to the colon, this is called resistant starch. Resistant starch functions like soluble, fermentable fiber. When it reaches the colon, it provides food for your microbiome, otherwise known as a prebiotic. When the bacteria digest the resistant starch, they produce short-chain fatty acids, especially butyrate, that have been shown to decrease rates of colon cancer. Some good sources of resistant starch are seeds, whole grains, legumes and green (unripe) bananas.
Fiber
Fiber is the part of the plant that your body can’t digest or absorb. It passes unchanged through your digestive system. Soluble fiber is fermented by the bacteria in your colon and so acts much like resistant starch. Sources of soluble fiber are beans, greens and potatoes. Insoluble fiber can’t be fermented by the bacteria in the colon but it does retain a lot of water so it’s known for promoting normal bowel movements. All food derived from plants will have some of each of these types of fiber, but at varying amounts. True whole grain is 90% insoluble fiber while oats are 50/50. There is no doubt that people with high fiber diets have less digestive issues and a lower risk of colon cancer.
So why are carbs so bad?
Carbs aren’t bad for you, in fact they are essential for life. They provide energy for your cells as well as perform other vital functions in your body. The problem lies in the type and amount of carbs you consume. Simple carbs will release a large amount of glucose quickly and will lead to a spike in your blood sugar. The problem is that your blood sugar levels will then come crashing down. The glucose levels will drop so low that you may feel shaky and fatigued. Your brain will then direct you to eat more simple carbs to stabilize your blood sugar level and the whole cycle starts all over again. Complex carbs will also increase your blood glucose levels but not as high or quickly as simple carbs.
Though complex carbs can contain high levels of vitamins and minerals, the extensive processing typically done to these foods leaves them fiber and nutrient depleted. Even worse, they have been so highly processed, what we call refined carbs, that they behave like simple sugars causing rapid glucose spikes in your blood. Refined carbs are typically found in many grab and go foods such as chips, crackers, sweet treats and breakfast cereals. However, even whole, starchy foods, such as potatoes, can also quickly drive up blood sugar. For instance, a medium sized baked potato has about 37 grams of carb with 6 grams of fiber. This means that 31 grams of glucose can be absorbed into your blood stream. The total carb minus the amount of fiber is the net carb amount in a food and the amount that will most likely affect your blood sugar. Ask any diabetic, what happens to their blood sugar level when they eat a potato.
Carbs and the FASST Plan
Two of the three pillars of the FASST Plan is to “fuel your body without spiking your blood sugar” and “to provide fiber to feed your microbiome.” It is this balance that is so important. You want to find foods that will provide some carbohydrates but are loaded with nutrients and fiber to address all of the needs of your body. So let’s say you want to increase fiber in your diet. You could chose to have a slice of wheat bread that has 128 calories, 24 grams of carb and 3 grams of fiber. This means there are 21 grams of net carbs that your body can turn into glucose and raise your blood sugar. Also there is no significant nutrient value. Compared to a cup of broccoli that has 31 calories, 6 g of carbs and 2.4 grams of fiber, leaving a net carb of 3.6 grams. And broccoli provides 135% of the daily recommended amount of vitamin C! That’s what I called nutrient packed. Some may argue that grains are a good source of fiber, but at the risk of spiking your blood sugar. Whole grain bread provides more fiber than white or wheat bread, but only 2 more grams of fiber per slice and again, with no significant nutritional value and 14 grams of net carbs. In the end, everything is a trade off, but if you are trying to increase fiber in your diet, it’s best to add foods that won’t spike your blood sugar at the same time.
If you want to know more about foods that won’t spike your blood sugar but provide you with plenty of carbohydrates, download the FASST Plan Quick Start Guide and play close attention to the “Core Four.”