"You should not be mixing your fruits and vegetables!" I've come across this post on Instagram too many times but no explanation behind it. As I continue to study and research the answer, this statement became very clear and worthy to understand.
Fruits and Vegetables are both in the carbohydrate family but both are labeled and process differently when entered into the body. The number one reason fruits and vegetables should not mix is that they digest and absorb differently.
Type of Carbohydrates
Starch (complex) - Grains, corn, rice, barley, vegetables, beans, and wheat
Sugar (simple)- Sweets (candy), sugar (cane sugar), fruit, and milk
*This is a correction for the Blog "Carb's aren't the Enemy."
Fruits do serve a great multitude of essential nutrients but still contains more sugar than vegetables.
Summary: Fruits are simple carbs not complex.
Although Carbohydrates are broken down into two types, complex and simple, they also are classified into sugar units (saccharides) which help the digestive system.
Classification of Carbohydrates:
1. Monosaccharides (One single sugar unit)
2. Disaccharides (Paired Sugar Unit)
3. Polysaccharides (Longer sugar unit)
4. Oligosaccharides (3 to 10 sugar unit)
Monosaccharides and Disaccharides are known as simple sugars where Polysaccharides and Oligosaccharides are known for complex sugar. Polysaccharides and oligosaccharides are broken down into disaccharides and disaccharides broken down into monosaccharides. This process helps the body to absorb most nutrients from our food and use it as energy.
Photo by: NASM Nutrition Study Guide
How are carbohydrates are digested and absorbed?
- As the food is entering the mouth it's mixed with salivary amylase (ah-muh-lace) and begins the digestion process.
- Once the food enters the stomach it's mixed with "gastric juices" to continue the breakdown process.
3. Small Intestines
- In the small intestines, the food is broken down into "monosaccharides" (mo-no-sac-ca-rides), and most nutrients are absorbed.
4. Portal Vein/ Liver Circulation
- Monosaccharides then enter the hepatic portal vein* for transport to the liver & cells.
*The vein that transports blood from the spleen, stomach, pancreas, and intestinal tract to the liver.
Fruits are labeled as monosaccharides, meaning, they consist of single sugar units and are digested at a faster pace than vegetables. Fruits also contain more sugar than vegetables. The mixture of the two can cause a delay in the breakdown of vegetables. In other words, the body will focus on breaking down a single sugar units than two or more.
When it comes to the Energy Pathways, both carbs are flown differently.
As discussed earlier, disaccharides (paired-sugar units) are broken down into monosaccharides(single-sugar unit) form. This allows the body to use this form as glucose. Reminder, carbohydrates' number one focus is to use as immediate energy. Glucose (complex carbs) feeds directly into the energy pathways with no problem while 35% to 45% of Fructose (fruits) is oxidized (gaining oxygen and removing electrons) in the energy pathways. (Sun & Empie, 2012).
When the immediate fuel needs are met, priority two for the surplus of carbohydrates (i.e., glucose or fructose) is to replenish liver and muscle glycogen. (NASM, Nutrition Certification). In other words, carbs (fuel or food) that are leftover will renew the liver and muscle glucose reserve. Glycogen is another word for reserve glucose. When the body is ready for immediate energy, again, it has the ability to breakdown glycogen into glucose.
From left-over carbohydrates, small pieces of glucose gathers together to build a bigger chain of glycogen (reserve glucose) where 40% to 50% of Fructose are converted to glucose in the cell for glycogen synthesis ( a chemical reaction of forming glycogen from glucose).
As you see, the body used glucose for immediate fuel. Fructose is required to be converted into glucose for energy or glycogen for later use.
This information seem to be confusing and a lot, trust, I know. However this differentiates the reason it's important to know how both carbs are digested. I can testify that this statement is true. It's not in the nutrition rule book that we shouldn't mix veggies and fruits but it's not in the rule book that we should. Our bodies are very unique and crafted in its own way. Just as God created the earth with wisdom, He did the same with our bodies. Our bodies are able to breakdown and absorbed anything that may seem too complex. Be kind to your body, get to know it day by day and you'll be surprised by what your body can do.
"Carbohydrates." Chapter 7, Lesson 1 & 2. AFAA Nutrition Coach Certification Study Guide.