How Much Carbohydrate Can You Store?

After ingestion, dietary carbohydrates have four metabolic fates (1,2):  

1. Used as fuel substrate and oxidized in several tissues of the body, mainly as glucose;

2. Storage as glycogen in skeletal muscle (80% stored) and liver; 

3. Storage as triacylglycerol (TAG);

4. Conversion of glucose molecules into C3 precursors in the splanchnic area which pass on to the liver where they are used as substrates for gluconeogenesis.

De novo Lipogenesis (The Conversion of Carbs to Fat) in Humans, and How You Get Fat

Stored fat may come from diet or de novo lipogenesis (DNL). De novo lipogenesis refers to the conversion of dietary carbohydrate (CHO) into fat.

The physiological functions of de novo lipogenesis are (1):

1. There are no functions (vestigial pathways in humans);

2. Necessary in embryonic development – for central nervous system lipid synthesis (vestigial pathway in the post-natal life);

3. Important on low-fat diets – suppressed by un-natural modern diet (vestigial pathways culturally);

4. Only important after long-term surplus carbohydrate (glycogen overflow pathway);

5. Serves signal or regulatory functions (eg. antiketogenesis, tissue fat oxidation, insulin synthesis, etc).

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

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

Abstract

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. 

AARR: The Female Athlete Triad – Epidemiology, Endocrinology, Assessment and Nutritional Intervention

Sérgio Fontinhas. The female athlete triad – Epidemiology, endocrinology, assessment and nutritional intervention. Main article, AARR, May 1st, 2016.

Abstract

The term 'Female Athlete Triad' refers to a pattern of inter-related symptoms of disordered eating, amenorrhea and osteoporosis in a number of female athletes. When these three medical conditions are present the effects are synergetic and cause a greater negative impact on health than each one alone.

Hydration and Exercise: Hypohydration and Exercise-Induced Hyponatremia

Changes in cell hydration are critically important for the signaling towards metabolic responses to hormones, substrates and reactive oxygen intermediates (1).

Hypohydration and exercise

Hypohydration during exercise strongly rises the catabolic hormonal response to resistance exercise, and increase circulating concentrations of metabolic substrates. Hydration status during exercise changes the endocrine and metabolic adaptive responses to resistance exercise and also changes the postexercise internal environment. Specifically, there’s increase in cortisol, epinephrine, and norepinephrine (2).

The Hierarchy of Fuel Selection - Which Fuel Do You Preferentially Burn?

The oxidative hierarchy follows the body’s relative storage capacity for the different substrates and their role in ensuring survival. In this context hierarchy=priority (of fuel selection)

1. Thus, the hierarchy is dominated by alcohol because the body has practically no storage capacity for it and must be eliminated by oxidative disposal through rapid hepatic oxidation (1,2,3).