Fasting Flashcards
Ketogenesis
occurs in mitochondria of liver
low insulin, high glucagon
Ketolysis
occurs in any tissue with mitochondria
Fuel Utilization
Day 1- Insulin levels begin to fall and glycogen is the primary fuel source
Day 2-3 Gluconeogenesis is utilized as the main fuel source
Day 3 – 40 Ketosis is the primary fuel source
What tissues use ketones?
Brain and heart in a resting state.
Need REST during a fast…exercise can induce protein catabolism thus gluconeogenesis
Hormones during fast: decrease
Insulin (Na diuresis results)
Insulin R
IGF-1
Thyroid
Hormones during fast: increase
GH Adiponectin Melatonin Cortisol Glucagon Epi
Stage 1 Fast
adaptation, 1-7 days
high cellular wastes and slowed elimination
malaise, HA, muscle aches, hunger
Stage 2 Fast
physical hunger subsides
healing crisis
tissue remodeling
Stage 3 Fast
starvation
gluconeogensis from protein catabolism
muscle tissue catabolized
organ failure
How long to fast…
until healing crisis or a significant detoxification
3-40 days
consider: reserve, metabolism, severity of dz, sex, schedule, etc
Complications
drop in BP hypothermia arrythmia weakness dehydration GI bleed gout dyspnea emotional distress
Contraindications to fasting
emaciation/malnut anemia polyuria lactation, preg, child acyl CoA DH def
Labs
UA CBC CMP -K decreases -liver enzymes my rise -uric acid and TG may rise
“fasting” every other day – 500 calories between 12-2 pm
Decreased CVD disease risk Weight loss Improved multiple parameters in Type 2 DM \+ effect on cancer risk Increased splenic SOD
