Sports Nutrition: Don’t Be Caught Running On Empty

If you have ever “hit the wall” while participating in a sporting event, you know exactly what I’m talking about.  It suddenly feels way more difficult to achieve the level of intensity that was possible even 5 minutes before; legs start to drag, arms feel hollow, and mentally it feels like an uphill battle (maybe literally and figuratively).

Hitting The WallIf you’re a Canadian reader, you may remember the heartbreak triathlete Paula Findlay experienced at the London 2012 Olympics.  Originally considered a frontrunner, Findlay finished last in the women’s triathlon event.  In her post event interview, Findlay described her legs feeling like lead in the water, during her cycle her legs felt empty and she was dizzy.

Paula Findlay

Her coaches said it was because of a hip injury but after some digging, turns out that the reason Findlay couldn’t garner the steam to get going in London was due to an iron deficiency.  For more on Iron, check out this post.  Though Findlay suffered from an iron deficiency, let’s start with the most common factor for poor performance during sport and that comes from a lack of energy.

Energy Pathways - Sports

In the world of sports nutrition, energy is created in units called ATP (adenosine triphosphate).  ATP is created quickly and anaerobically (without oxygen) for activities that are short in duration and high in intensity (think sprints and weightlifting), however, when exercise starts to exceed a couple of minutes the aerobic system kicks in.  Aerobic energy is created more slowly than its anaerobic counterparts, however, the number of ATP units produced are much more plentiful.

Energy Pathways

In all but the initial 6 seconds of activity, ATP comes from the breakdown of glycogen or fat.  When we eat carbohydrates, they are broken down until single units called glucose.  While a small amount of glucose circulates in the bloodstream for immediate energy, the vast majority of it is stored in the muscles as glycogen for future energy needs.  When we have superseded our glycogen store capacity, glucose is stored as fat.

In order to have adequate energy, it’s essential that we are consuming enough glucose to fill our muscles with glycogen – our stored form of glucose that comes from carbohydrate based foods.  Of course other macronutrients like fat and protein offer their own sports related advantages, but for this post, the focus in purely on obtaining and maintaining energy.

STEP 1:  make sure that you’re eating enough carbohydrate daily.  The number of grams of carbs required can be calculated using the table below.

Activity   Level grams of   carbohydrates/kg of body weight/day
3-5 hours/week 4-5 grams
5-7 hours/week 5-6 grams
1-2 hours/day 6-7 grams
2-4 hours/day 7-8 grams

For example, if I work out 7 hours a week and have a weight of 60 KG’s (pounds/2.2 = weight in KG) then I should be eating between 300 and 360 grams of carbs per day.  NOTE:  when speaking about grams of carbs, I’m not referring to the weight in grams.  Rather it is the amount of carbohydrate available in a serving size.  Check the nutritional information to see how many grams of carbohydrate are available in a typical serving size.

Nutritional Label

STEP 2:  When selecting your daily carbohydrates (ie: not right before, during or after a sporting event) choose the right type of carbohydrate.  Instead of differentiating between simple sugars and complex carbohydrates, it may be more useful to instead select carbohydrates based on their Glycemic Index value.  Each food has an inherent GI value; low is 0-55, medium is 56-70, and high is 71-100 and it is generally considered more advantageous to choose lower GI foods.  The reason for this is that lower GI foods result in a slow and gradual release of glucose and allow for more stable blood sugar levels – in fact low GI diets are associated with a decrease risk for heart disease, Type II Diabetes, bowel cancer, upper gastrointestinal tract cancer, and pancreatic cancer.  Examples of lower GI carbohydrates include:

Fruit:  apples, pears, oranges, grapefruit, peaches, nectarines, plums, apricots, berries.

Veggies:  pretty much any veggie except for starchy vegetables.

Multi Grain Breads, oats, muesli, bran cereals

Wheat or bulger pasta, basmati rice.

Beans and lentils

Nuts & Seeds

Fish, Chicken, Eggs

Low Fat Dairy

Pre-Workout Snack

Pre-Workout Snack

STEP 3:  Have a snack 1-2 hours before a workout.  It seems that lower GI carbohydrate choices allow more fat to be burned in comparison to glycogen during a workout.  What this means is that you will keep your endurance up for a longer period of time because glycogen stores are being depleted at a slower rate.  Aim for 30-60 grams of carbs 1-2 hours before your workout or event.  This could include fresh or dried fruit, a granola bar, or a homemade smoothie (add some leafy greens for increased nutrient density!).  Check out this great site for 50 pre-workout snack ideas.


STEP 4:  Re-fuel appropriately during exercise.  It’s said that there is no need to eat during exercise lasting less than one hour.  If you’re participating in an endurance type event, then you must ensure you’re getting 30-60 grams of carbs each hour – the best type of carb to consume in this case would be a higher GI carbohydrate so that the energy hits your system quickly.  It takes Carbs about 30 minutes to be digested and absorbed so when participating in an event longer than an hour, it’s crucial to start your hourly 30-60 gram carb intake within the first 30 minutes of exercise.  There are various gels, sports drinks, and gummies to choose from which can be purchased at any health food/nutrition/sports store.  In Canada, try The Running Room.

STEP 5:  Replenish your glycogen stores after exercise to speed recovery and help prevent fatigue and hypoglycemia.  It’s important to consume about 1 gram of carbohydrate/KG within two hours – choose low GI carbs if you are workout out only once in a day and high GI foods if you engage in multiple same day workouts.

Stay tunned for more on sports nutrition and an upcoming post on a diet fit for muscles and strength!

THE DAILY DL (Dalai Lama)

“Champions aren’t made in the gyms. Champions are made from something they have deep inside them — a desire, a dream, a vision.”

– Muhammad Ali


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