The Ketogenic Diet Flashcards
What is the Ketogenic Diet?
diet enriched in calories from fat with
minimal calories from carbohydrates and
protein that promotes ketogenesis
– Classic (standard) ketogenic diet has 90% of
calories derived from fat
– Remaining 10% of calories from carbohydrates and
proteins
– 4:1 ratio by weight (fat:carbs/protein)
4 g of fat = 1g of protein
body makes 3 ketone bodies
Fatty acids need to be converted into acyl-CoAs in order to be oxidized
• Hence, fatty acid oxidation is required for ketogenesis
• There are 3 different ketone bodies in our circulation
– βOHB
– Acetoacetate
– Acetone
βOHB – β-hydroxybutyrate
repsiring acetone, fruity breath
Why do our bodies undergo adaptive ketogenesis
physiologically?
• Why do our bodies undergo adaptive ketogenesis
physiologically?
1) Our body has small reserves of carbohydrate
(glycogen), 1 day’s worth of carbs
2) Our body has limited protein stores, dont want to breakdown for energy
3) Our body has plentiful fat stores as triacylglycerol in
adipose tissue
4) Our brains are unable to oxidize fatty acids for energy (fasting for prolonged periods)
• A ketone body is a pre-catabolized fatty acid (in liver) that
can be metabolized/oxidized by the brain
Ketoacidosis
• Circulating ketone levels
– Normal = 0.2 mM
– Fasting = 1 – 3 mM
– Diabetic ketoacidosis = levels can be >25 mM (blood pH: 7.25-7.3 [mild], 7-7.25 [moderate], <7.00 [severe])
• Considered at risk of diabetic ketoacidosis if blood
glucose > 16.7 mM and blood ketones > 1.5 mM
• Diabetic ketoacidosis is the leading cause of death in
people under 24 years old who have diabetes
elevated ketones is ok as long as pH of blood is maintained
During Initial
Starvation/Fasting
explain diagram slide 10
mobilize fat during fasting/starving
brain can’t metabolize those fatty acids
muscle protein broken to aa into liver –> gluconeogenesis turns into glucose to fuel brain (not advantageous to breakdown muscle protein)
ketogenic diet:
body keeps mobilizing adipose tissue and liver make ketone bodies, sounds like you will lose weight
What Happens When you
Eat Some Carbohydrates?
• Insulin inhibits adipose tissue lipolysis and fatty acid metabolism • Insulin promotes glucose uptake into the muscle, heart, adipose tissue and liver • Hence, insulin shuts off ketogenesis!
inhibits fatty acid oxidation, decrease fat to liver
T1D need it or ketoacidosis risk is high
Therefore the Ketogenic Diet…
Makes the body behave like it’s fasting and
continually produces ketones
1) The low carbohydrate intake keeps insulin levels low
2) Low insulin levels activate mobilization of triglyceride
stores in the adipose tissue
3) The liver will oxidize the fatty acids in the diet and
convert them into ketones
4) Overtime consumption of this diet can promote
weight loss
▪ Continuous mobilization and loss of adipose tissuederived fat that the liver continually turns into ketones
Variations of the Ketogenic Diet?
– Standard ketogenic diet: 90% of calories derived from fat and 10% calories from carbs/proteins. In general 20- 50 grams of carbs per day
– Targeted ketogenic diet: consumption of 25-50 grams of carbs 30-60 min prior to exercise
– Medium-chain triglyceride diet: majority of fat intake
comes from medium-chain triglycerides
– Modified Atkins diet: carbohydrate intake remains
limited at 10%, but protein content is increased to 30%
– Low glycemic index diet: Carbohydrate intake is limited to foods with a glycemic index < 50
what are there variations of keto diet?
Variations of the ketogenic diet are often aimed at increasing carbohydrate and/or protein content in order to improve palatability of the diet (an important consideration from the pediatric perspective)
hard to adhere to with high fat diet
Where is a Ketogenic Diet Used in Medicine
• Children with drug-resistant epilepsy (DRE)
– Incidence of epilepsy ranges from 41 – 187 per 100 000 children.
– 1/3rd of these children will be resistant to current
pharmacological therapies.
– Studies show that children with DRE may have as high as a 50% reduction in seizure frequency after 6-months of ketogenic diet consumption.
– Reversal of protective effect rapidly diminishes following discontinuation of the diet
• Has been employed for treatment of refractory
epilepsy for over 90 years
– To mimic the biochemical changes associated with fasting.
• Mechanism of action for this benefit is
unknown
– Activation of potassium channels and membrane
hyperpolarization?
– Increased GABAergic neurotransmission?
– Increased mitochondrial function?
– Decreased plasma glucose levels?
Where is a Ketogenic first line therapy?
• Individuals with glucose transporter 1
(GLUT1) deficiency
– A rare genetic disorder characterized by seizures,
developmental delay, and movement disorders.
– GLUT1 transports glucose through the the blood brain
barrier through brain capillary endothelial cells.
• When should a ketogenic be avoided?
– In people with carnitine deficiency (cant oxidize fat without it)
Adverse Effects of the Ketogenic Diet
• Metabolic abnormalities – Hypoglycemia – Excessive ketosis (metabolic acidosis) – Electrolyte Imbalances • Dehydration – More common in ketogenic diet protocols that include fasting • Gastrointestinal symptoms – Abdominal pain – Vomiting – Constipation
• Kidney stones
– Ketogenic diet-associated risk of kidney stones
ranges from 2 – 6%
• “Fruity” breath
– We eliminate acetone mainly via respiration in the
lungs
Over-the-counter medications may contain
carbohydrates
Can reverse ketosis and precipitate seizures again
in children taking a ketogenic diet for their drugresistant epilepsy
Ketometers and Ketone Strips Can be
Purchased from the Pharmacy
How many individuals
on a ketogenic diet
actually check their ketones?
blood b-ketone test strips
s the Ketogenic Diet Actually Beneficial
for our Everyday Health?
• Most of our clinical evidence lies in the field of
epilepsy (for children)
– What does this evidence tell us?
low qualirt of evidence
effective in children with epilepsy, doens’ matter which variation
