In college I majored in sport science and human performance, which meant the bulk of my course load centered on exercise science, sports nutrition, kinesiology, exercise physiology, etc. and nearly all the research I did involved athletes. One of the topics we spent a lot of time covering in my sports nutrition class was the various diets that athletes maintain while in-season, during the off-season, and in the immediate days leading up to competition. Today’s post is going to talk about one of those strategies – carbohydrate loading – and it’s effect on your performance during a race. (Spoiler: there’s not much benefit.)
The role of carbohydrates in the body and during exercise
During high intensity exercise, carbohydrates are the main energy source. CHOs also function as the only fuel for red blood cells, your brain, and nerves. If you deplete your CHO stores, for example during strenuous exercise, your blood glucose will be maintained by breaking down lipids and eventually some protein – lipids are fine but you never want to be breaking down proteins because that means that all other sources of energy have been maxed out so your body now has to rely on its skeletal muscle tissue (which is made up of protein) as a last-ditch energy source. This reverts back to everything I talked about in February regarding eating disorders.
During exercise, CHOs are the preferential fuel because they rapidly supply ATP via oxidative processes that allow them to be delivered twice as fast as fat and protein. During anaerobic activity (such as the start and sprint), they are the sole suppliers of ATP. Having a low CHO intake for three consecutive days has been shown to lead to a decrease in anaerobic exercise capacity, which means that if you’re not getting enough carbs in your diet during the week your body will be physically unable to go as hard at the beginning and end of a race, which is why it’s important to make sure you’re eating well-balanced meals all the time (regardless of what weight-class you’re competing in).
CHO-loading as an ergogenic aid
Ergogenic aids are defined as “any method or practice that serves to enhance energy utilization, including energy production, control, and efficiency.” There are several different types of ergogenic aids, some legal (CHO loading), some illegal (blood doping), some mechanical (in the context of rowing, rigging would be an example of this), and some psychological (hypnosis), amongst others.
Related: Intro to rigging
We spent a lot of time talking about the history of ergogenic aids because most people assume that they were developed or thought of recently – in fact, they’ve been in use since the original Olympic games. The ancient Greeks actually believed the “you are what you eat” mantra and to become better competitors, they’d eat the raw meat of lions and tigers because lions and tigers were/are powerful, swift, aggressive, fast, and deadly when on top of their game, which is what we as athletes all strive to be when we compete.
The mechanisms of CHO-loading involve super-compensating the stores of glycogen in the muscles and liver. The pros of doing this include:
Increased time to exhaustion (TTE) in activities lasting longer than 90 minutes and performed at a moderate to high level of intensity (marathons being the main example)
Increased TTE in intermittent high intensity sports (tennis, for example)
Improved endurance by about 20%
Improved performance by about 2-3%
The only major con is that there may be a disturbance in the body’s overall energy balance, meaning that the diet may lack other necessary macronutrients (the other two macronutrients being protein and fat). It’s also been shown that there is little or no effect on high intensity bouts of exercise lasting less than five minutes in length.
Below is a slide I did for a presentation on supplements for a class on issues and controversies in nutrition. We’d just gone over this stuff on ergogenic aids a couple days before this project was assigned so I was able to use all the info from my physiology class for my nutrition class. The yellow, orange, and red table at the top gives you a brief overview of what your CHO intake should look like in the week leading up to a race, which in this case was on a Sunday.
If your diet is made up of about 70% carbohydrates, as you progress through the week (Monday through Thursday) you would gradually decrease the amount of CHOs in your diet. Monday would be 60%, Tuesday 50%, Wednesday 40%, and Thursday 20%. During this time you are still training, although you tend to scale back a little as the week progresses (also known as tapering). On Friday and Saturday you ramp back up the amount of CHOs in your diet (where the term “supercompensate” comes from), from 20% to 75 and 80%.
CHO loading and rowing
Something you might have noticed from that slide and in what I mentioned earlier is that it says “endurance sports” and only talks about the increased TTE in events lasting longer than 90 minutes. So, this would lead one to believe that CHO loading before a sprint race wouldn’t do much to enhance your performance, which for the most part would be correct. CHO loading is better suited for something like a head race where you’re going at 100% for 20-30 minutes, although even then any performance benefits would be small.
To ensure your energy supplies are topped off before an event, your best bet is to eat a pre-competition meal about three hours ahead of time, although it’s important to remember that this meal alone cannot and will not make up for having a poor chronic diet. Ideally you’d be eating something with 150-300g of carbs (3-5g/kg of body weight) while being sure to avoid anything containing high fat or protein contents. The advantages of a meal like this are that they replenish your glycogen stores, it requires less energy to break down, nutrients are absorbed faster, digestion is quick, and it serves as the main source of energy for short term anaerobic/high intensity aerobic exercise, which is basically exactly what a sprint race is.
On the flip side, if you eat something immediately before you go out and race, you end up with a spike in your blood glucose levels which results in a hyper-insulinemic response. Because of the surge in insulin being released, your blood glucose then plummets which in turn leads to your performance being not so great. This is why you should avoid eating anything within thirty minutes of your race.
So, what should you actually eat?
There are so many options. Seriously. Pasta is not the only food with carbohydrates – bagels, peanut butter, honey, raisins, whole-wheat bread, apples, brown rice, yogurt, sweet potatoes, etc. are all examples of good staples in a rower’s diet.
If you’re going to commit to CHO loading, you should spend the time to work out exactly how many grams of carbs you should be eating/how much you need and then determine the number of carbs/calories in the foods you’re ingesting. If you’re in college and are taking a nutrition class or know someone who is, ask to borrow whatever book they’re using. Most basic nutrition classes require textbooks that tend to have long, long, long lists of foods in the back from every food group that list amount of macronutrients they contain. If you can’t do that, you can search whatever food you’re trying to look up and the awesomeness of Google will tell you right on the search page the number of carbs that food contains. If you don’t trust Google, I suggest using the USDA’s website. All you have to do is open up the “carbohydrates” report – you can open it with the foods listed either alphabetically or by nutrient content, which has the foods with the highest amount of carbs listed first.
Vegetarians, vegans, and CHO loading
There’s a lot of controversy on athletes who are vegetarians or vegans since the majority of them don’t eat any animal by-products, which cuts out a lot of the foods that their carnivorous counterparts rely on to maintain adequate energy stores. When attempting to CHO load, the options are pretty much the same for the most part, the only difference being they would need to look into gluten-free options and replace the meat and dairy with more vegetables, lentils, beans, tofu, chickpeas, etc. If there are any vegetarian/vegan rowers out there who wouldn’t mind sharing the foods they eat when prepping for a race, that’d be great.
Moral of the story…
Carbo-loading for sprint races is pretty much pointless. It’s a little more understandable for head races but in essence this is a tactic best reserved for straight endurance athletes, which rowers are not. You’re better off eating a diet rich in protein (see the slide below this) than trying to ingest large amounts of carbs that you most likely won’t fully burn off.
That isn’t to say that you shouldn’t be eating a solid amount of carbs too, because obviously you should be, but when comparing the benefits of CHO loading (remember, that’s super-compensating the amount of carbs you’re taking in) vs. ingesting protein, the more applicable benefits to rowing come from diets with adequate amounts of protein in them.