Can a keogenic diet affect gluconeogenesis?

Hi Nolan,

Interesting question! And thanks for getting me to review some physiology that I haven't looked at much since graduate school!

I've got a question question for you - how do you know if someone is in or out of ketosis? Are you testing for ketones?

Hi Lauren, thanks for replying. I believe it was by using ketostix, which measures the ketone levels in the subjects urine. I wouldn't know the level attained but from what I understand the most recent test tested negative for any ketones.

OK, so first, in an effort for full disclosure my patients are only in ketosis when their diabetes is totally out of control, and therefore, I do not feel comfortable recommending a ketogenic diet nor am I super familiar with ketogenic diets to achieve muscle hypertrophy.

That being said, after reviewing some references, this is what I found. Glucose is our body's preferred source of fuel for exercise and it prefers to obtain glucose from carbohydrates. If carbohydrates aren’t available, the body looks elsewhere to make glucose to meet the body’s energy needs (gluconeogenesis).

The amino acids, the building blocks of muscle proteins, are able to participate in energy metabolism when energy demand increases and there aren’t adequate carbohydrate stores to meet the demand. It has been proposed that alanine, one of the amino acids that make up our skeletal muscles and is released by muscle during exercise, may indirectly contribute to meeting exercise energy requirements via the alanine-glucose cycle.

During exercise, alanine is released by the exercising muscle into the bloodstream where it travels to the liver. The liver is where the body makes glucose. Once in the liver, alanine loses the amino molecular group, the part that makes it an amino acid, and converting alanine into pyruvate, which is then converted into glucose via gluconeogenesis and is released back into the bloodstream where it is transported to the muscle for energy.

So knowing this, it seems that you and I have a similar hypothesis about what’s going on. The client increased her training, creating an increased need for energy by the muscles and the body used up whatever carbohydrate stores were available so it then turned to the additional protein to create the additional glucose required to meet her new training demands.

Perhaps someone else might be able to provide some additional insight?

That's good to read. I believe I read somewhere that the the percentage of protein converted into glucose via gluconeogenesis changes when the body enters ketosis. Typically around 55 to 60% of protein is converted into glucose and stored however when the body is in ketosis the it's requirements for glucose drops day by day. This is good for a person in a calorie deficit as it spares their lean muscle mass from being broken down into glucose.

I believe the client is on a ketogenic diet for the purposes of reducing their fat as opposed to assisting their hypertrophy.

Many thanks for your input Lauren!

Hi Nolan,

From what I've read, it seems that when the body starts depending on proteins in the skeletal muscle for energy, the lean body mass, specifically, muscle tissue, is decreased. I have seen this process of protein breakdown described as a similar process to that which occurs during starvation to ensure that the central nervous system, which depends solely on glucose for its ability to function, is receiving adequate energy. Therefore, carbohydrates are a protein sparer, and maintaining an adequate carbohydrate consumption prevents lean muscle mass from being used up as energy.

The consensus amongst large medical and sports medicine assocations is to recommend a reduced calorie diet following general diet recommendations coupled with regular exercise to achieve weight loss. However, I suspect, this client might be wanting to achieve more than just a lower number on her scale...

Thanks for this great question and discussion!!

"From what I've read, it seems that when the body starts depending on proteins in the skeletal muscle for energy, the lean body mass, specifically, muscle tissue, is decreased."
This is why dietary protein intake was increased to approximately 1g per pound of body weight, to offset the body's requirements for glucose by breaking down muscle mass.
I totally agree - carbs are a must, even if only from vegetables and fruit. Her calories are quite high due to the level of activity she participates in. I just found out that, once in ketosis, she lowered her fat intake in favour of replacing the calories with protein so it looks like the theory was indeed the case.

Many thanks for the info! It was an interesting subject to review!

Good to hear! Thanks again! I learned something new today!

Hi Guys,

I think in practice, fairly high-protein diets (even over 1 gram per pound of bodyweight) can still lead to ketosis. We experimented with keto sticks years ago with some bodybuilders who often dieted most days on around 20 grams of digestible carbs or less (we tried to keep their fibre intake at 35 grams or more - otherwise the plumbing gets messed up - but this obviously wouldn't contribute to glucose supply) and they were producing ketones. Although they were consuming a hypocaloric diet, so this may have necessitated ketone production for brain function if glucose was being directed to their huge, hard-training musculature.