Gluconeogenesis: The Sugar Factory Inside

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Carbohydrates, Glucose, and Glycogen

Gluconeogenesis

That is why there is no such thing as “essential carbohydrates.”

Cultures with Low Carb Diets

Why is a High Carbohydrate Diet Bad?

Can the Liver Overproduce Glucose?

Large Amounts of Visceral Fat = Wide Waist Circumference

High Carbs → ↑ Visceral Fat → Metabolic Syndrome → Deadly Diseases

Take Away Message.

Carbohydrates, Glucose, and Glycogen

In all cultures in the world, there is always a source of starch for every meal. It may be rice, bread, pasta, noodles or tubers like potatoes, and cassava. It is commonly believed that you have to have starch as a source of energy. That is true. All of the above contain carbohydrates that are digested and broken down into glucose. Glucose is then used as fuel by the body and the brain. It is stored in the liver and muscle as glycogen. Glycogen is a complex molecule formed by chains and branches of glucose. In a 70 kg man, about 100 grams of glycogen is stored in the liver, and about 400 grams of glycogen is stored in the skeletal muscles.

The liver and skeletal muscle maintain 4 grams of glucose in the bloodstream at any given time as a constant source of energy. The brain does not store glucose, and yet it uses up 60% of glucose present in the blood. The muscle glycogen is used as a readily available source of fuel for muscle contraction and movement. Awake or asleep, our body uses glucose for energy.

Gluconeogenesis

If the liver contains only a small amount of glycogen, (less than a small bag of Doritos Nacho Chips), what happens then when it’s level starts to get low? What if we missed a meal? Does our body shut down like a car when the gas tank is entirely empty? Do we drop dead?

No, we don’t. There is a metabolic system in the liver called gluconeogenesis. Gluconeogenesis means to make new glucose. Glucose from gluconeogenesis is the same in form and function as dietary glucose, but they are made from the components of protein, fatty acids, and intermediates from carbohydrate processing.

That is why there is no such thing as “essential carbohydrates.”

There are essential amino acids and essential fatty acids that we need to eat because our body cannot make them. In the case of glucose, the body can efficiently produce it.

Cultures with Low Carb Diets

That explains why some cultures survive even though they eat a small number of carbohydrates. Examples are the Maasai tribe in Africa who mostly eat milk, meat, and blood, and the Inuits from the Arctic who eat mostly fat and meat. Common among these two population groups is not only a low carbohydrate diet but also the small risk of hypertension, hypercholesterolemia, atherosclerosis, and coronary artery disease.

Why is a High Carbohydrate Diet Bad?

The typical diet nowadays is high in carbohydrates. Remember that the body can only store a total of about 500 grams of carbs as glycogen. If we are sedentary (not exercise) and don’t use up that glycogen, the carbs get stored as fat. Some fat gets stored inside our abdomen as visceral fat. As the visceral fats get larger, it starts to secrete hormones and pro-inflammatory substances that lead to diabetes, hypertension, atherosclerosis, heart disease, and strokes to mention a few. So remember, carbs make you fat!

Can the Liver Overproduce Glucose?

In people with Type 2 Diabetes, also known as Adult Onset diabetes, the body does not respond to the effects of insulin (insulin resistance) therefore the liver produces more glucose to counter the insulin resistance and to “push” the glucose into the cells. Fasting makes the body insulin sensitive again. For people without diabetes, gluconeogenesis does not make your blood sugar high because the hormone insulin controls how much glucose is produced.

Large Amounts of Visceral Fat = Wide Waist Circumference

Visceral fat can be easily and indirectly measured using an inexpensive tape measure. In front of a mirror, at the level of the belly button, wrap the tape measure around your waist, making sure that the tape does not sag. In males, the IDEAL waist circumference should be less than 101 cm/ 40 inches (men), Asians 90 cm/ 35 in or 89 cm/ 35 inches (women), Asians, 80 cm/ 31 in.

High Carbs → ↑ Visceral Fat → Metabolic Syndrome → Deadly Diseases

The waist circumference is a criterion to assess whether you have the metabolic syndrome. Having metabolic syndrome leads to diabetes, atherosclerosis, hypertension, coronary artery disease and strokes.

Take Away Message.

Prevent the formation of visceral fat by eating a low carbohydrate diet. (20 – 60 gms/day). The body can burn fat to make glucose.
Increase the visceral fat loss with intermittent fasting.
Increase visceral fat loss with high-intensity interval training (HIIT) and/or resistance training.

If you have or are taking medications for diabetes, hypertension and heart disease, talk to your doctors before starting fasting and an exercise program.

[1] “Medical gallery of Mikael Häggström 2014.”