By Coach Quinn
Disclaimer – for the purpose of this article, the assumption will be made that all other variables are held constant. Eg. protein intake, micronutrient variety, fibre consumption, suitable level of fats for healthy hormone levels/cellular health etc. *
The article will also discuss carbs vs fats specifically in the context of performance, not weight loss, although, the conclusions of both are similar.
Introduction
Chances are if you’ve done any kind of google search on what you should eat for ‘losing weight as quickly as possible,’ ‘how to get 6 pack abs with Mike Chang,’ or if you’re like me, ‘how to get so shredded your forearms look like a leaf,’ then by now you will have come across a lot of contradicting information in a war between the high fat and high carb zealots. The issue is, unless you’re willing to do a degree, you’re probably using “how to flatten your stomach with this MLM fat burning celery stick” on Karen’s latest booty pic from Instagram as your source for a nutrition guide.
Now, because I love this stuff, I’m simply going to do you a solid by cutting out all the bullshit and give you the big facts behind high carb vs high fat in the most easily digestible way possible.
Energy Systems
Context in nutrition and movement performance is super important when deciding which energy source is superior: sport chosen, personal preference, what you enjoy eating, goals, adherence, sustainability etc. So, in order to determine which is “better,” we must first distinguish which energy systems are being used in our various activities.
Without going too deeply down the rabbit-hole of anaerobic (without Oxygen) and aerobic (with Oxygen) metabolism, we have three main energy systems:
- ATP-PCr
- The Glycolytic Pathway
- The Oxidative Phosphorylation Pathway [made up of the Kreb Cycle (which I am beyond sick of looking at, shout out to my Science major gang :P) and Electron Transport Chain].
The first two [ATP-PCr and Glycolytic Pathway] are our anaerobic systems, they provide majority of the energy transfer required during high intensity activity, e.g., lifting a barbell or swinging on that pullup bar. This is because oxygen uptake simply cannot keep up with the demands of this form of exercise. The last system of Oxidative Phosphorylation, as suggested by the name, requires oxygen to be present. An example of this aerobic pathway would be going for a barefoot marathon run or doing a 1000 burpee challenge.
Being majority CrossFit athletes, we perform in a mixed modality-based exercise, using both anaerobic and aerobic.
*It is important to note that all energy systems will be used at the same time constantly, however the activity being performed will determine which is more dominant in energy transfer*
For anaerobic activity to occur, the body will breakdown glycogen (stored carbohydrates); being approximately 100g from the liver and roughly 350-700g in muscle tissue depending obviously on the individual, use immediately available blood-glucose or “break” the glycerol backbone from triglycerides to replenish energy. For this system to be in effect, we absolutely need glucose as it is the only nutrient that can enter the cycle for energy transfer.
For aerobic activity to occur, it also requires carbohydrate metabolism. Without an adequate carbohydrate intake, people will often feel rather sluggish or lethargic, e.g., me at Frantic Day Out.
If this real struggle-town situation occurs, the liver won’t have enough stored glucose to ship to the brain, muscle tissue or red blood cells. As a consequence, everything from physical activity to mental cognition may diminish to match the reduced nutrient/energy availability.
HOWEVER,
Does that mean everybody right now needs to go out and start smashing a loaf of bread and a litre of choccy milk everyday like I used to? I mean, I’d personally say get a beer funnel and start chuggin’ but in reality…probs not hey.
This is because your body is a beast at adapting. We can handle a lot. Simply put, if our bodies were that sensitive to change, we would all be dead in a day. After 1-2 weeks of low carb intake, which is defined as being less than 60-100g depending on the individual per day, people with enough body fat and adequate dietary fat consumption, will begin to compensate with KETONES [three main types are: B-hydroxybutyrate, acetoacetate and acetone] for energy transfer. The ketone bodies are then converted to supply brain, muscle tissue and RBC’s with energy transferring nutrients. (YES, IT TAKES UP TO 2 WEEKS TO GET INTO KETOSIS, NOT 45 MINUTES LIKE KAREN’S BOOTY PIC CAPTION WOULD HAVE YOU BELIEVE)
Once this switcheroo has occurred, some individuals may feel awesome while others will remain feeling like absolute shit, in which case, moderate to high carb intakes will probably be key for them.
Resistance Training on High Fat
Your body has certain amount of glucose that it 100% needs for multiple physiological processes. This amount is typically about 100-120g (again depending on the individual) and is required because red blood cells can only exclusively use glucose, the central nervous system uses majority glucose, and finally as mentioned above with the most relevance in a practical sense to all of you is muscle cells during anaerobic exercise can only use glucose.
Another HOWEVER.
Once again, your body is so goddamn good at adapting, because through a process called gluconeogenesis, we can produce glucose from other non-glucose substrates (gluconeogenic substrates).
SO, even if for some bizarre reason you are managing to consume ZERO carbohydrates, if there is a compensatory amount of fats in your diet, then the body will be able to produce the required amount of glucose itself.
Although fats can certainly compensate our energy supply, the process of gluconeogenesis isn’t perfect, so if you are trying to do high intensity anaerobic exercise like majority of us then you MAY see some deterioration in athletic performance. Restoring muscle glycogen and blood-glucose levels for easy access to anaerobic and aerobic activity is still going to be king for performance. Most of the workouts we do in CrossFit and Fiit will require some form of higher intensity activity or longer sustained effort. Regardless of which, carbohydrates will more than likely be our most readily available macronutrient due to dedicated storage of carbohydrates and for it having the fastest gastric emptying time of all three macronutrients.
*if you are dabbling in a form of high GI carbohydrates such as maltodextrin or cluster-dextrin for pre/intra/post-workout, the recommendation I would make would be to keep it at 7-8% of solution when mixed with water. This is to avoid as much gastric upset as possible. For example, 45g of Clusterdextrin mixed with 600mL of water = 7.5% of solution. Nobody wants an upset tum when trying to out high hang snatch their mates (looking at you Gov).
*OR IF YOU’RE ON A BUDGET LIKE I AM, A PACKET OF GUMMY WORMS WILL ALSO PROBABLY DO THE TRICK, THEM THINGS BE DELICIOUS*
Now contrast that to if you were using fats as a pre-workout (which typically have the slowest gastric emptying of the macronutrients). Are you really going to be able to blend up a roll of brie or munch on a stick of butter? I highly doubt it.
In conclusion, for my athletes that are engaging in multiple CrossFit-based and Fiit-based strength & conditioning training sessions per day or doing endurance training such as preparing for a triathlon, you will more than likely require the most amount of carbohydrates. This is because your ability to perform will be primarily dependant on the relationship between fatigue and glucose depletion. You’ll need to replenish your stored glycogen for the following day (fun fact: majority of our energy each day is sourced from the stored glycogen from yesterday), and to ensure you have a steady supply of high GI carbohydrates pre|intra|post workout to keep blood-glucose levels at an optimal level.
As for the majority of people that will actually read this article, doing an hour of CrossFit, Fiit, resistance training, or time restricted endurance training, you will burn less calories throughout the duration of your activity. This means that you will deplete far less glycogen in comparison to higher tier athletes. The good thing for you guys is that your nutrition intake can be far more balanced depending on your own personal preference of whether you want to smash some cheddar cheese or if you want to plough through a bowl of cocoa bombs. Adherence and sustainability are going to be far more paramount for your overall health, wellbeing and sustained performance. – Coach Quinn
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Berardi, J., Andrews. R, Pierre. B, Scott-Dixon. K, Kollias. H and C. DePutter. The Essentials of
Sport and Exercise Nutrition. 3rd Ed. Certification Manual. 2018 Mar;04.
Kulik JR, Touchberry CD, Kawamori N, Blumert PA, Crum AJ, Haff GG. Supplemental
carbohydrate ingestion does not improve performance of high-intensity resistance exercise. J Strength Cond Res. 2008 Jul;22(4):1101-7. doi: 10.1519
Paoli A, Grimaldi K, D’Agostino D, Cenci L, Moro T, Bianco A, et al. Ketogenic diet does not
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