Carbohydrate Disposal – a Priority. Science Driven Nutrition. Vol 2. December 2015

Sérgio Fontinhas. Carbohydrate disposal – a priority. Science Driven Nutrition. Vol 2. December 2015


The oxidative hierarchy refers to the relative order in which fuels (alcohol, carbohydrates, protein and fat) are selected for oxidative disposal after ingestion. Giving the relative storage capacity for these different substrates, each fuel assumes different priorities within metabolic pathways. These physiologic alterations serve to channel energy to and from the appropriate storage compartments under all circumstances that may challenge the organism. 

The hierarchy is dominated by alcohol, followed by carbohydrate and protein, and fat at the bottom. Alcohol, carbohydrate and protein elicit powerful auto-regulatory mechanisms - they promote their own oxidation – while fat does not. 

Glycogen stores can maximally accommodate 800-900g of carbohydrate and perhaps as much as 1000-1.100g in trained athletes. When glycogen stores are saturated, massive intakes of carbohydrate are disposed of by high carbohydrate-oxidation rates. Along with a progressive carbohydrate oxidation, basal metabolic rate and total energy expenditure also increases. 

Another pathway to dispose of carbohydrates is de novo lipogenesis, however this process is quantitatively small in humans.

Key words: Carbohydrate, glycogen, fuel selection, lipogenesis, oxidation

1. Fuel storage capacity
1.1 Alchool
1.2 Carbohydrate 
1.3 Protein
1.4 Fat

2. Substrate flux and hierarchy of fuel selection
3. Carbohydrate disposal
4. Lipogenesis