Download MBBS The Feed Fast Cycle Lecture PPT

Download MBBS (Bachelor of Medicine and Bachelor of Surgery) Latest The Feed Fast Cycle Lecture PPT


THE FEED-FAST CYCLE
OVERVIEW OF THE ABSORPTIVE PHASE
The absorptive (well-fed) state is 2-4 hrs period after

ingestion of a normal meal

During this interval, transient increases in plasma glucose,

amino acids and TAG is seen

Islet tissue of pancreas responds to elevated level of

glucose with increased secretion of insulin and decreased

secretion of glucagon

The elevated insulin/glucagon ratio and the ready

availability of circulating substrates make the absorptive

state an anabolic period characterized by increase

synthesis of TAG and glycogen as well as increased

synthesis of protein
During this absorptive period, virtually all tissues use

glucose as a fuel, and metabolic response of the body

is dominated by alterations in the metabolism of liver,

adipose tissue, skeletal muscle and brain
LIVER:NUTRITION DISTRIBUTION

CENTER

The liver is uniquely situated to process and distribute

dietary nutrients because the venous drainage of the

gut and pancreas passes through the hepatic portal

vein before entry in to general circulation

Thus, after a meal, the liver is bathed in blood

containing absorbed nutrients and elevated levels of

insulin secreted by pancreas

During the absorptive phase, the liver takes up

carbohydrates, lipids and most amino acids

ADIPOSE TISSUE: ENERGY STORAGE

DEPOT

Adipose is second only to liver in its ability to

distribute fuel molecule

In a 70 kg man, white adipose tissue weighs around 14

kg or about half as much as total muscle mass

Nearly the entire volume of each adipocyte in WAT

can be occupied by anhydrous,calorically dense TAG

SKELETAL MUSCLE

Skeletal muscle accounts for nearly 40% of the body

mass in individuals of healthy weight and it can use

glucose, amino acids, and ketone bodies as fuel.

Skeletal muscle is unique in being able to respond to

substantial changes in the demand for ATP that

accompanies muscle contraction

At rest, muscle accounts for 25% of oxygen

consumption of the body ,whereas during vigorous

exercise ,it is responsible for up to 90% of total

oxygen consumed
BRAIN

Although contributing only 2% of adult

weight, brain accounts for a consistent 20%

of basal oxygen consumption of the body

at rest

In the fed state, brain exclusively uses

glucose as a fuel ,completely oxidising

140g/day to carbon dioxide and water


OVERVIEW OF FASTING STAGE

Fasting begins if no food is ingested after the absorptive

period

It may result from inability to obtain food, the desire to

lose weight or clinical situation in which an individual can

not eat

In the absence of food, plasma level of glucose falls,

triggering a decline in insulin secretion and increase in

glucagon, epinephrine and cortisol secretion

Decrease insulin/glucagon ratio and decreased availability

of circulating substrates make the postabsorptive period a

catabolic period characterized by degradation of glycogen,

TAG and protein
Starve cycle is divided in two four stages:
Early fasting (4-16 hrs after food)

Prolonged Fasting (16-48 hrs after food)

Starvation (2-3 days without food)

Prolonged starvation (>5 days without food)



This post was last modified on 30 November 2021