FASTING - 4 researches have been study and the metabolism is described in this powerpoint. In this pandemic, how fasting can be useful..in this situation. a medical book of biochemistry was also helpful to get the information about fasting metabolics switch.

1. FASTING
Ritu Ahirwal
Student of BNYS

2. INTRODUCTION
Fasting is the willful refrainment from eating
and drinking.
Fasting may refer to the metabolic status of a
person who has not eaten overnight, or to the
metabolic state achieved after complete
digestion and absorption of a meal.

4. TYPES OF FASTING
1.Intermittent Fasting (IF)
This eating pattern involves fasting for varying
periods of time, typically for 12 hours or
longer.
2.Calorie Restriction (CR)
This eating pattern involves a continuous
reduction in caloric intake without
malnutrition.

5. TYPES OF FASTING
3.Restricted Feeding (TRF)
This eating pattern involves restricting food
intake to specific time periods of the day,
typically between an 8 – 12 hours each day.
4.Alternate Day Fasting (ADF)
This eating pattern involves consuming no
calories on fasting days and alternating fasting
days with a day of unrestricted food intake or
“feast” day.

6. TYPES OF FASTING
5.Alternate Day Modified Fasting (ADMF)
This eating pattern involves consuming less
than 25% of baseline energy needs on
“fasting” days, alternated with a day of
unrestricted food intake or “feast” day.
6.Periodic Fasting (PF)
This eating pattern consists of fasting only 1 or
2 days/week and consuming food ad libitum
on 5 to 6 days per week.

7. BENEFITS
• Placing time restrictions on feeding has been
shown to have broad systemic effects and
trigger similar biological pathways as caloric
restriction. For example, IF regimens have
been shown to improve cardio-metabolic risk
factors (such as insulin resistance,
dyslipidemia and inflammation cytokines),
decrease visceral fat mass , weight loss.

8. What is this metabolic switch and how
is it flipped?
• One key mechanism responsible for many of
these beneficial effects appears to be “flipping”
of the metabolic switch.
• Body’s preferential shift from utilization of
glucose from glycogenolysis to fatty acids and
fatty acid-derived ketones.
• This switch represents a shift from lipid synthesis
and fat storage to mobilization of fat in the form
of free fatty acids (FFAs) and fatty-acid derived
ketones.

9. Continued...
• The metabolic switch typically occurs in the third
phase of fasting when glycogen stores in
hepatocytes are depleted and accelerated
adipose tissue lipolysis produces increased fatty
acids and glycerol.
• The metabolic switch typically occurs between 12
to 36 hours after cessation of food consumption
depending on the liver glycogen content at the
beginning of the fast, and on the amount of the
individual’s energy expenditure/exercise during
the fast.

10. PHASES OF GLUCOSE HOMEOSTASIS

11. Continued...
• Periodic flipping of metabolic switching not
only provides ketone bodies as a fuel source
during fasting period, but also regulates
expression of many proteins and molecules
that can influence health and aging.

12. WITHOUT FASTING

13. DURING FASTING

14. BETA OXIDATION OF FATTY ACIDS
• The lipids in adipocytes (triacylglycerol and
diacylglycerol) are metabolized to FFAs, which are
released into the blood . Simultaneously, other
cell types may also begin generating ketones,
with astrocytes in the brain being one notable
example.
• FFAs are transported into hepatocytes where
they are metabolized by β-oxidation to produce
the ketones β-OHB and acetoacetate, which may
in turn induce mitochondrial biogenesis.

15. KETONE BODIES
• 1) Acetone
• (cannot be metabolised)
• 2) beta- hydroxybutyrate
• (does not possess a keto group {C=O})
• 3)Acetoacetate

16. KETONE BODIES METABOLISM

17. Continued...
• Thus, it appears when the metabolic switch is
flipped, the primary energy source for the
body shifts from glucose to FFA derived from
adipose tissue lipolysis and ketones, which
serve to preserve muscle.

18. CORONA vs FASTING
• In one study done on Switching Host Metabolism as an Approach
to Dampen SARS-CoV-2 Infection in sept. 2020.
• Fasting or intermittent fasting (IF) has been shown to exert
beneficial effects in patients with underlying co-morbidities,
including various chronic diseases, and also to prevent diseases in
healthy subjects, reducing oxidative stress and inflammation.
Indeed, C-reactive protein (CRP) and inflammatory bio-markers
such as IL-6 have been shown to be significantly decreased by short
and long IF .
• On the other hand, caloric restriction (CR) also reduces markers of
oxidative stress and inflammation and metabolic disease risk
markers among patients with moderate asthma and other
respiratory diseases. Many authors recommend diet with CR,
fasting (e.g., Ramadan fasting) or IF to boost the human immune
system.

19. Another study
• Switching body metabolism from fed/feasting
state to a fasting state involves systemic and
cellular remarkable adaptations .
• This can cause an increase in ketones
(acetoacetate and β-HB), increase in
mitochondrial stress resistance, increase
antioxidant defenses, increase autophagy
(cleaning out damaged cells), increase DNA
repair, decrease insulin secretion.

20. Continued...
• Dietary factors, specifically lipids, to effectively
reduce inflammation and oxidative stress, thus
strengthening the immune response during the
COVID-19 crisis.
• Bioactive lipids with antiviral properties cited in
the literature include certain long-chain
monounsaturated fatty acids (MUFAs) and
medium-chain fatty acids (MCFAs), specifically
lauric acid (LA). LA, the primary fatty acid of
coconut oil, is a saturated MCFA with potent
antimicrobial properties

21. Continued..
• coconut oil is metabolized to produce the
metabolite monolaurin.
• Medium-chain saturated fatty acids such as LA
and long-chain unsaturated fatty acids (such
as oleic acid of olive oil) are highly active
against enveloped viruses such as coronavirus
• Monoglycerides of these fatty acids also show
significant antiviral activity.

22. Antiviral activity of lauric acid
1) LA and monolaurin inactivate viruses by
disintegrating the viral envelope, thus
reducing the infectivity of RNA and DNA
enveloped viruses.
2) LA inhibits the late maturation stage in the
virus replication cycle
3) LA prevents the binding of viral proteins to
the host cell membrane

23. Continued...
• The substantial evidence for the antiviral
properties of LA (commonly found in coconut
oil) is promising and encourages its further
investigation as a potential therapeutic agent
that is both affordable and clinically innocuous
for SARS-CoV-2-infected patients.

24. • A breakfast enriched with ketogenic MCT via
coconut oil enriched with LA/caprylic acid and
monounsaturated long-chain fatty acid (oleic
acid 18:1 omega-9) from olive oil rich in
antioxidant and anti-inflammatory bioactive
phytochemicals. Breakfast with more protein
foods prepared with MCT oil (coconut oil) can
trigger the ketogenic pathway and hence
supposed to repress the viral replication.

25. • Following breakfast supplemented with 20-g
ketogenic MCT drink and keeping an 8–12 h
fasting can trigger the ketogenic pathway and
allow for cellular activation of the autophagy
pathway and hence proposed to ameliorate
the SARS-CoV-2 viral replication. At lunch
time, subjects are given 20-g ketogenic MCT
drink without a meal.

26. • After the 8–12 fasting period, a dinner with a
balanced diet can provide the required
amount of carbohydrates, and fibers from
fruits and vegetables rich in vitamins and
minerals are important for boosting the
immunity against SARS-CoV-2 infection.
•

27. BIBLIOGRAPHY

28. BIBLIOGRAPHY
• Narimen Yousfi, Nicola Luigi Bragazzi, Walid
Briki,Piotr Zmijewski, Karim Chamari .The
COVID-19 pandemic: how to maintain a
healthy immune system during the lockdown
– a multidisciplinary approach with special
focus on athletes.biolsport.2020,May
19; 37(3): 211–216.

29. BIBLIOGRAPHY
• Sameh Soliman, MoezAlIslam E. Faris, Zakaria
Ratemi, and Rabih Halwani . Switching Host
Metabolism as an Approach to Dampen
SARS-CoV-2 Infection.Ann Nutr Metab. 2020
Sep 18 : 1–7 .
• Textbook of Medical Biochemistry. Dr.
S.K.Gupta. 2nd Edition, Pg. No. 323-337