Hydration: It is important to maintain adaquate hydration. Even minor dehydration has big consequences. You will slow approximately 2% for every percent of body weight lost to dehydration. This means that a runner who does a 40 min 10km will run over a minute and a half slower when just 2% dehydrated. A good tip is to weigh yourself before and after your training runs. You don’t want to see a weight loss above 2% of your total body weight.
But it’s more than just water. Your body also needs electrolytes (sodium and potassium). These are lost in your sweat. Your muscles and nervous system are very specific in the concentrations they require. Sports drinks are formulated to be easily absorbed and replace those lost electrolytes. You’ll also need to replace sugars. After 90 min of exercise you will have spent all of your glycogen stores (quickly usable carbohydrate stores in your muscle and liver). A 6% carbohydrate solution is isotonic, or roughly the concentration found in your body. I like powdered drinks so that I can alter the concentration slightly to see what works best for me in different situations (hot days, cold days, etc).
Sip your drink before you run to make sure you’re topped up. For longer runs, carry some drink with you on your run. Generally, I won’t bother carrying fluids for runs under 10km as I can wait until after the run. And, just like you should never try new shoes on race day, never use a new drink on race day. Some people get digestive upset with a change in type of drink. You don’t want to find that out in the middle of a 10km race. If the race organisers are providing sports drink that you don’t train with, carry your own. Some people like caffeine added drinks. Caffeine is a stimulant and improves your use of fat for energy. But can your system handle it? Some people find that caffeine is a “gastric motility aid.” This can present a problem when you are in the middle of a run. Again, best to experiment during training runs.
Day to day eating: I think it goes without saying that you will need more calories than your couch potato buddies. In fact, your metabolism is elevated for at least 24 hrs following exercise. This does not mean, however, that you can eat empty calories. Sure, one of the benefits of exercise is you can have that donut, just don’t have the whole dozen. You must still eat well.
You’ll need more vitamins than the standard recommended daily allowance (RDA). A by-product of exercise is that you produce free radicals. Free radicles can damage your DNA and lead to premature aging or even cancer. Vitamins A, C, and E are anti-oxidants and prevent free radicals from damaging DNA. Many long distance runners are anemic, as red blood cells are crushed as they circulate through your feet as they pound the pavement. Your red blood cells simply won’t last as long as the average person’s. As such make sure you are getting enough iron through foods such as red meat, salmon, spinach, brocoli or lentils. I must point out that I am a big advocate for getting your nutrition from real foods made from scratch, rather than supplements or processed garbage.
A common mistake amonst health conscious runners is to eat a low fat diet. This is a mistake. It has been shown that runners that runners a low fat diet are far more likely to get stress fractures (fractures due to repetitive trauma). This is especially true of female runners. To prevent this, make sure 30% of your energy comes from fat, just keep the ratio of healthy polyunsaturated fats high compared to less healthy saturated fats.
It should be noted that vegetarian runners must put a lot of planning in their diet as it can be difficult to get ehough protein, iron, zinc and possibly B12.
- Originally, this was done as follows: The athlete does a high intensity workout 7 days before event (to deplete stores), 2-3 days of low carbohydrate diet (to further deplete stores and lead to carb starvation mode), then 3-4 days of high carb diet where body stores more glycogen than normal.
- Most people now just do the high carb diet for the 3-4 days prior to race day and this works very well.
- An even newer method is done in one day: the day before race the athlete does a 2:30 minute sprint, then a short rest followed by 30sec flat out sprint. The athlete then has a high carb diet for the day. This has been shown to work well, but I still stick with the second method as it works well and the method is more established.
Race Day Nutrition: One of the most common running questions is what to eat on race day. It is an individual thing. What works for me might not work for you, but here’s some general guidelines.
Eat breakfast roughly 2 hours before your race. This gives the stomach a chance to clear it’s contents so it’s not sloshing around when you run, but will still have these nutrients in your bloodstream ready for use. Any longer than this and you may be dipping into your energy stores.
Choose calorie dense slow energy releasing food. Here’s my typical pre-race breakfast: 2 slices of toast with peanut butter, glass of fresh orange juice, oatmeal with maple syrup, 1-2 bananas (tend to eat these in the hour or two before race). I also like having a latte prior to leaving the house as well. Try to avoid figh fibre diet items as this may give you a bathroom emergency in the middle of the race! It’s best to test-run your breakfast on training days leading up to the big day.
Speaking of which, an article about running nutrition wouldn’t be complete without discussing:
runner’s trots: Many runners find they are plagued by runner’s trots where part way into a run they develop diarrhea or have a strong need to defecate. Some possible causes include: vitamin c supplements, high fibre diet items immediately prior to the run, sorbitol (common sweetener in sugar-free gums) and stress. Some people find that refined carbohydrates (ex. white bread rather than whole wheat) in the lead up to the race can help.
So there’s a short summary of running nutrition. Lots more could be written, but that covers the basics. If you have any specific questions or want to share your running diet naightmares, leave a comment below. Until next time, I’m Dr. Jason Hare, Pure Chiropractic, Nanaimo.