Glucose is a simple sugar molecule component of dietary carbohydrates, including starches and sugars, that is found in plant sources of food, such as fruits, vegetables, legumes and grains. Your body uses glucose for energy; however, under certain circumstances, it can make glucose from amino acids that come from the proteins you eat.
Amino Acids
Proteins are broken down into individual amino acids during digestion, which takes place in the stomach and small intestine. They're absorbed through the intestinal walls into the bloodstream. Normally, amino acids are used to build new proteins that maintain your tissues and organs, and any extra amino acids are converted to fat for storage. However, if you don't consume a sufficient amount of carbohydrates, the amino acids will be converted to glucose by your liver.
Gluconeogenesis
Gluconeogenesis is process of creating glucose from sources other than carbohydrates. Although most of it takes place in the liver, a small amount occurs in the kidneys. There, amino acids are degraded into carbon skeletons that are converted into a substance called pyruvate, which goes through a series of steps to become glucose, which is then absorbed into the bloodstream to provide energy for the rest of your body.
High-Protein Diets
Gluconeogenesis usually takes place during fasting times when you haven't eaten any food recently, such as the hours when you sleep. However, high-protein, carbohydrate-free diets stimulate gluconeogenesis to occur after your eat, which may burn more calories than carbohydrate metabolism. A study published in 2009 in "The Journal of Clinical Nutrition" found gluconeogenesis stimulated by such a diet increased energy expenditure in healthy volunteers.
Low-Carbohydrate Diets
Low-carbohydrate diets promote the restriction of carbohydrates and can potentially cause your body to break down the proteins in your muscle tissue to supply the amino acids used in gluconeogenesis. According to "The Ketogenic Diet: A Complete Guide for the Dieter and Practitioner," consuming adequate amounts of protein during a ketogenic diet will prevent muscle wasting because your body can use the amino acids found in your diet for gluconeogenesis.
References
- Virtural Chembook, Elmhurst College: Glycogenesis, Glycogenolysis, and Gluconeogenesis
- National Digestive Diseases Information Clearinghouse (NDDIC): Your Digestive System and How It Works
- "The American Journal of Clinical Nutrition"; Gluconeogenesis and Energy Expenditure After a High-Protein, Carbohydrate-Free Diet; M. Veldhorst; July 2009
- "The Ketogenic Diet: A Complete Guide for the Dieter and Practitioner"; L. MacDonald; 1998
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