Ketosis. It’s a pretty sexy topic right now and just about everyone’s friend, aunt and uncle seem to be an expert on being fat adapted. Lately I've been asking myself "shouldn't I eat carbs when I want to perform a high powered sport or exercise?"
This post isn’t meant to be a focus on what ketosis is, but for the sake of context, I’ll give you the main points. Ketosis is a metabolic state where our body switches from glucose to ketone bodies (which are derived from acetyl CoA) when we deplete our body of glucose and glycogen. Ketone bodies are produced as a result of our body breaking down fat. If the brain prefers glucose as fuel, then how are we able to survive on prolonged fasts? That’s because those ketones take the place of glucose and can fuel the brain. In a clinical setting, ketogenic diets have been utilized for the treatment of MS, diabetes, cancer and Alzheimer’s. *** Quick note: MS and Alzheimer’s have been tied in with mitochondrial dysfunction and the brain cells inability to use glucose to fuel the brain. The idea is that switching to ketone bodies will serve as an alternative fuel source instead of glucose. Aside from its effects on MS and Alzheimer’s, endurance athletes have started to adapt a more ketogenic based diet in order to take advantage of the fact that fat, as a substrate is vast and almost endless. Think about it, we can store more fat than glycogen bro! Note that there is something called nutritional ketosis (keeping carbohydrates under 50g) and fasting ketosis (when were eating almost nothing).
If you're geeked out on body metabolism and want some cold hard facts…Just know that ketosis is measured by the amount of ketone bodies present in our blood. True ketosis can fluctuate but should be at about 0.2-0.5 mm of BHB (hydroxybutyrate is just one measurable ketone). Anything over this means you've been "kicked out of ketosis".
- Ketones can be used as an alternative source of fuel for the body.
- Ketones are produced when our body metabolizes fat.
- Ketosis is used as an alternative fuel source in clinical settings when mitochondria (energy producing area) are not using glucose effectively.
- We can store more fat than glycogen.
- Ketone bodies made from acetyl CoA.
Since were all experts on ketosis, lets tackle the real question. Is ketosis good for athletes who require short bursts of power? Is it for everyone?
I remember having a conversation with a naturopath and asking him what his thoughts were on performance and running on mostly fat aka ketosis. I remember his exact words “yeah fat would be an ideal energy source if the sport was fighting to the death”. What he meant was, fat is ideal when its our last option, but for shorter more powerful sports, we’d be best served with some high quality carbohydrates.
I also remember talking to a colleague of mine and debating whether or not being fat fueled was the ideal state an athlete should be in. The outcome was an agreement that endurance athletes would be best served using fats as fuel because it enables the athlete to be more metabolically flexible and tap into an almost unending source of fuel. However, in order for this to work the athlete would have to be “fat adapted” at least 3 moths before. We can’t just have the athlete attempt to get into ketosis 3 weeks before a triathlon.
My own personal experience? Ketosis was the easiest and least painful way for me to improve body composition (aka lose fat). However I can’t lie to you, if power is needed on a specific day, then clean carbohydrates work well for me. I follow a diet that's high in fat and protein but not exclusive to other macronutrients. I'll still eat carbohydrates and I'll eat them closer on days where I've played hockey or lifted something heavy. If I were to take part in a triathlon, then ketosis would make sense, but I'm not signed up for any at the moment. There’s an up and coming market for exogenous ketones on the rise and they’ll say that you can reap the benefits of ketosis by ingesting ketones which will allow you to use ketones without going into fasting or nutritional ketosis. I’ve tried this as a sample and it was tasty, but I’d have to use it longer to feel the performance enhancing effects.