‘Pie hole’, colloquial for one’s mouth, is believed to have evolved in the USA in the 1980s from the British expression ‘cake hole’ (coined in the mid 20th century). Pie hole refers to a mouth, as in: Shut your pie hole or, in this case: Put less in your pie hole.

Wednesday, December 19, 2018

Being Held Up By Keto Bandito?

The keto diet is so popular right now for weight loss... It seemed only fitting that I return from maternity leave with a topic shrouded in controversy. Dieters and wannabe nutrition "experts" tout this diet for weight loss and fat burning. But does the science agree?

Below is Q&A about the keto diet. I hope I've buttered you up enough to chew the fat with me as we explore the fats... I mean facts.

Question #1 - What is the origin of the ketogenic diet?
The ketogenic diet was originally developed as medical nutrition therapy for children with epilepsy. Further, some research shows a keto diet may benefit people with certain cancers, and neurological conditions. In these cases, the diet is administered as therapy under the guidance of a dietitian and doctor.

Question #2 - What is ketosis?
"Keto" is a super cool name, who wouldn't want to say they're on the keto diet? It's almost as catchy as gluten-free. But what is ketosis? To understand it we need to rewind, get a little technical, and understand some physiology:
  • Our brain needs carbohydrates for energy
  • Glucose is the simplest carbohydrate, and the brain's preferred energy source
  • When we decrease our carbohydrate consumption dramatically (to ~20g of carbs per day) our body uses up its glucose stores (glycogen)
No, you're not in ketosis yet.
  • Your body is using amino acids (the building blocks of protein) to create glucose, a process called gluconeogenesis (remember for later)
  • The body is no longer able to manufacture a compound called oxaloacetate, needed for normal fat breakdown via the Krebs/Citric Acid Cycle 
    • Insufficient oxaloacetate means another compound, called acetyl-CoA, builds up 
    • Acetyl-CoAs interact with each other and form ketone bodies: acetoacetate (AcAc), β-hydroxybutyric acid (BHB) and acetone
    • Ketones are formed in the liver but the liver cannot actually utilise them for energy
      • Amino acids are used to create new glucose (gluconeogenesis, remember?)
      • Glycerol is also used to make new glucose, glycerol is liberated during the breakdown of triglycerides (fats stored in your body)
    • Ketones can cross the blood brain barrier and are used as an alternate energy source
Bottom line: The process of producing ketones and remaining in ketosis is complex and requires very strict and precise carbohydrate (and protein) restriction.
Question #3 - Is it hard to maintain ketosis?
Yes. The classic keto diet requires 4% of calories come from carbohydrates, 6% from protein, and 90% from fat. That's <20g of carbs per day. To put that in perspective, it is currently recommended that 45-65% of calories should come from carbohydrates (>50% whole grain), 10-35% from protein, and 20-35% from fat.

There are a variety of keto diet adaptations, however, in my research for this article it's clear that larger amounts of carbs and protein hinder ketosis.
Unlikely to keep you in ketosis

It's really difficult to achieve and actually maintain ketosis. Keto is a very restrictive diet, requiring precise monitoring and weighing of foods. Too many carbs means the citric acid cycle can function normally to break down fats without producing ketones (described in Q#2). Too much protein and your body will convert the amino acids into glucose (gluconeogenesis).

Bottom line: Chances are higher than not that you are not actually maintaining ketosis.

Question #4 - Is ketosis beneficial for weight loss?
Yes, BUT... 

There is significant weight loss at the onset of the keto diet (up to 10lbs in 2 weeks). This is due to water loss (glucose is stored with water, water is heavy.) Most people want to lose fat, not water. No one ever asked "do I look watery in this outfit?"

Due to the restrictive nature of the keto diet, long term compliance is low. Meaning dieters "fall off the bandwagon", and it's well documented weight regain is common in such scenarios. Think about it... you go back to eating normally, glycogen stores are replenished... glycogen contains water, remember? 

Some research shows greater weight loss with the keto diet compared to other diets. This research is specific to obese patients with ongoing physician monitoring.

Bottom line: The keto diet, if maintained beyond 2 weeks often does result in weight (and eventually fat) loss, but the cost is high - see Q#6. And there's a difference between weight loss and fat loss.

Question #5 - How does ketosis help with weight and health?
These are some proposed mechanisms of action:
  • Appetite reduction due to the satiating effect of protein, effect on hormones controlling hunger, the possible effect ketones have on suppressing hunger (1, 2, 3)
  • Reduced lipogenesis (creation of fats) and increased lipolysis (fat breakdown) (1, 2, 3)
There is research documenting possible improvements in blood pressure, insulin sensitivity, and glycemic control.

Bottom line: The exact way weight/fat loss is achieved isn't fully understood, it's likely a combination of factors. 

Question #6 - Are there side effects to the keto diet?
Yes. Ranging from constipation to malnutrition. Deficiencies in calcium, vitamin D, selenium, magnesium, phosphorus, iron, essential fatty acids and prebiotics. Both constipation and deficiencies are due to the scarcity of fiber-containing foods that also contain vitamins and minerals (fruits, vegetables, whole grains, and legumes.) 

Many research papers and articles written by experts cite the importance of monitoring renal (kidney) function. How many of your gym buddies do this?

Ketones raise the pH of blood and a side effect of this is the removal of calcium from bones, called demineralisation which, over time increases the risk of osteoporosis. 

Another side effect is high levels of LDL cholesterol - the "bad" cholesterol (1, 2). This is not a surprise when one's diet is a scoop of fat with a side of fat.

Bottom line: Eating meat, butter, and oil will leave you
Insert face-palm emoji
constipated and lacking many vitamins and minerals needed to maintain proper health and function. Such high-fat diets tend to contain large amounts of saturated fat...BOOM, high LDL cholesterol.

Question #7 - Should you start or continue the keto diet?
To keep this somewhat unbiased, instead of answering the question, here's a checklist to ask yourself:
  1. Is it enjoyable to follow a very restrictive diet?
  2. Do you want to cut out things you enjoy eating?
  3. Think about what you know of a healthy diet. Does it seem healthy to eat huge quantities of fat and miniscule amounts of other things that have stood the test of time like fruit, veg, whole grains, legumes?
If I were answering this checklist, here are my dietitian-biased answers:
  1. Blech, no. I don't want to weigh my food, count my calories, or cut my carbs.
  2. Hell no. I love foods from every food group, especially chocolate (that's a food group, right?)
  3. Umm, no. I do not regularly eat sticks of butter.
    You're probably not...