You are what you eat

Author: Mike Kelly, PTS, CPR.
You’ve often heard "you are what you eat" but what you may not know, from an exercise perspective, is that when you eat can play a pivotal role in how you’ll perform.

If you’re eating healthy, proper timing of nutrition will allow you to exercise with less fatigue and soreness and prepare you for the next day’s exercise. We all know a good healthy breakfast is important (because between morning and noon is when you’ll burn a lot of your daily caloric requirements), but what if you are going to exercise at noon and don’t have time for lunch – that’s a big mistake, as you run the risk of low blood sugar (that weak feeling). So, make sure you’ve also had a good healthy snack 30 minutes to an hour before your noon exercise.

The Window of Opportunity

Generally speaking, say you had a run yesterday and posted a PB. Now, today you’re ready to impress your boss on the squash court with your new found speed, but early into the match, you feel extra tired – you need only look at what you ate immediately after your run yesterday to see the cause of your fatigue. Although fat is a great source of energy for aerobic exercise, e.g., a slow jog pace, it’s mostly carbs you’ll burn during anaerobic exercise, e.g. when posting a PB. Thus your body taps its supply of quick carb energy stored in your muscles and liver in the form of glycogen. Glycogen is greatly depleted in an hour or so (e.g., muscle fatigue). This is the time when you have to think smart as to what and when you eat, or shall we say, "the window of opportunity". For about two hours after anaerobic exercise, the body will work efficiently to convert and store carb intake. The storage process occurs over a longer period than 2 hours, but to get that hours worth of glycogen you burnt off, it needs to be done in the 2 hour time window. Specifically, it is done by eating high glycemic index foods that quickly convert into glycogen. For the average person, you should be taking in approximately 60 grams of carbs per hour for the first few hours – a sport drink has approximately 66 grams per litre, while an energy bar has about 30 grams. There is also a great food on the market called a "banana" that has approximately 27 grams of carbs. After this time window, then shift to taking in more complex carbs (lower glycemic index) targeting some 400 to 600 grams over the next 24 hours (this is based on your body s

size and that 57% of your daily caloric intake should be carbs). Should you miss the window, because you feel too exhausted to eat/drink, the overall time your body takes to restore your glycogen levels, will be greatly increased. So instead of replenishing the body’s stores in 24 hours, it might take 48hours. If you haven’t fully replenished this glycogen and take on the boss for an anaerobic game of squash, you’ll be just that, squashed.

The Pause That Refreshes – The Other Part of the Equation

We all know how important water is to our body, right? Just in case, here’s a "refresher" on what water does.

Water is not just for quenching thirst, but is important for many other things, e.g. water hydration helps cool the body down; reduce the burn from muscle fatigue; cushioning of our joints and efficiency of the heart just to name a few. Assuming your nutrition is good, you shouldn’t need anything other than water to replenish lost fluids during an hour of exercise. The only trick is to make sure you are well hydrated before beginning. So how does one know if they are well hydrated? Well you need only look as far as the washroom. Specifically, if your urine is closer to being clear than yellow, you are probably well hydrated. Alternatively, you could monitor your resting heart rate each morning. On days where your RHR is somewhat high, you can bet that you are probably not well hydrated.

Granted, it’s not easy to maintain good hydration. The reason for this is that you’ll only be typically reminded to drink, when you’re thirsty and by then it is too late to maintain good hydration. Okay, so how much water should one take in? Target about 1/2 oz per body pound for normal daily activities. This is a lot more water than you’re probably used to, so remember, "out of sight, out of mind" – keep a full water bottle with you throughout the day. If you’re exercising, you’ll also need to replace the fluids that you perspire out and depending on your body size and exercise intensity that can vary from 16 to 48oz. in an hour. If you’re going beyond 2 hours, consider a sport drink for lost sodium and potassium etc. Oh and let’s not forget about the caffeine we drink, which as a diuretic, you’ll need to drink 4oz. of extra water for every 8oz. of caffeinated fluids. Speaking of drinking, 3 glasses of alcohol per day can reduce the body’s ability to heal itself – so think moderation and you’ll feel better the day after that hard workout (late night hockey players take note).