Question

Evaluate one the states in the Fed-Fast cycle and how each tissue (liver, muscle, adipose tissue, brain, red blood cells and kidneys) is affected by this state

Answer 1

Normally human body derive energy from macronutrients like carbohydrates,fats/lipids and proteins. Metabolism is chemical reactions helps in maintaining the living state of cells and the organisms. The process of metabolism includes catabolism and anabolism. Catabolism involves in breakdown of the molecules to generate energy. Anabolism involves in synthesis of compounds needed for the cell growth. Carbohydrates are metabolised to form glucose, proteins forms aminoacids, fats metabolised into lipids.

Fed fast cycle an important stages in body metabolism. It consists of four stages namely : Fed stage, Post absorptive stage, Fasting stage, Starvation stage.

Fed stage lasts for 3 hours after meal ingestion. Post absorptive stage ranges from 3 hours to 18 hours after a meal. Fasting state sustains for 18 hours to 2 days without taking any food orally. Starvation refers to long term fast follows even for a week.

Carbohydrate metabolism in liver :

In fed state in liver the glucose converts into glycogen and fatty acids and this glucose is utilised by nervous tissues.red blood cells and fat tissues to generate energy.

In Post absorptive state glycogenolysis and gluconeogenesis (formation of new glucose to synthesize energy)

Fasting state the gluconeogenesis occurs with the utilisation of aminoacids, glycerol,lactate. The end waste product generated during this state is ketone bodies.

Starvation state :fatty acids are used in a greater extent. The major source of energy is glycerol.