TECHNICAL APPENDIX G: NUTRITION

As the old saying goes “an army marches on it’s stomach”. Well, skiers ski on theirs! Mealtime is a time to recharge physically and psychologically. Proper nutrition increases stamina and alertness, and therefore safety. Many athletes are confused about their nutritional needs. Yes, backcountry skiing can be termed an endurance sport and because of that may require higher amounts of carbohydrates as exercise fluctuates. However, it must be based on sound nutrition. You can’t live on power bars and athletic gels! You need fat, proteins and carbohydrates. Today’s skiers should resist fads and build a solid and disciplined approach to nutrition.

Nutrition and Altitude
At altitude, nutrient absorption is not impaired, but the hunger sensation is dulled. Accompanying weight loss is often referred to as high-altitude anorexia. Even well-trained individuals may lose weight at altitude even though caloric intake remains the same as at sea level. This phenomenon may be caused by a combination of both neurological and biochemical imbalances due to reduced oxygen pressure at altitude. Physiologists consider any altitude changes exceeding 6,000 feet (1,829 meters) a physiological change in altitude. Any such gain can decrease the appetite for food and water between 40 to 60 percent of normal. Whatever the reasons, the bottom line is that you need to eat while at altitude even though you may not feel like it.

Present Issues
Two areas that need attention are the amount of water that should be consumed and the ratio required between fats, carbohydrates and protein.

Water Intake
The figures for water intake are all over the place. Some say that you should be drinking 8 oz/1 cup per hour while others say just drink when you are thirsty. The common wisdom “drink 8 glasses of water a day” has no scientific basis. Dartmouth physiologist Heinz Valtin (2002) reviewed 30 years worth of hydration studies. The daily intake was approximately 4 glasses per day. One nice thing about the new “camelback” hydration systems is that you can take in many small amounts over time. This is the same way you should be eating as well. I like to pre-hydrate before

I go skiing, since I drink coffee which I feel dehydrates me. I feel better if I match my coffee intake cup for cup with plain water. Coffee is OK if you are already a coffee drinker. Coffee is one of the few true ergogenic drinks (work enhancing) since it is a mood elevator and stimulates fat metabolism during exercise. More water intake information can be found at the Gatorade Sport Science Institute web site: www.gssiweb.com. including a water intake calculator.

Fats, Protein, and Carbohydrates
Some climbers tell the joke that “cliff bars (energy bars) should be a food group”. As much as I like energy bars and energy gel, they are not a substitute for good nutrition and real food. The problem with these energy products is that they require a lot of water for their assimilation. If you don’t do this you can really get dehydrated. There is a story of two climbers (I won’t name names) who climbed the Polish Route on Denali and ate cliff bars and gel for two days. When they got to the medical camp at 14,000 after the climb they were greatly dehydrated and required intravenous rehydration.

Recent research shows that you need 25% fat, 15% protein and 60% carbohydrates for strenuous exercise at low to high altitudes. This ratio has been used on Everest climbs and at sea level during the Steger Arctic expeditions. After a hard day of exercising outside peanut butter and cheese really tastes good. That because our fat stores are decreased and fat is really brain food. Exercise demands mental work as well as physical work. Chocolate is also like coffee in that it is a stimulant that effects the same neuro pathways. Carbo loading like eating a big pasta dinner the night before a big ski day is a good idea and it works well.

There definitely is a place for carbs and energy bars and that is right during exercise when you are really in it. I like the newer packs that have the small pocket right on the belt just for energy bars. There is nothing wrong with adding energy powder to your water. But don’t make it too strong since your stomach can absorb it. In fact your stomach will suck water from your body to dilute it so it can absorb it and in the process make you drier which negates the whole reason you drank it in the first place.

You can’t eat all you need in three meals. You have to eat like a bird, eating several mini meals spaced over the whole day. The body can also absorb more nutrients from smaller meals than larger ones, because the body’s blood flow is concentrated on the muscles during skiing rather than on the stomach. It’s important to actually schedule food and water breaks ahead of time because altitude and exercise blunts your hunger and thirst.

Adding Up The Numbers: Nutritional Demand
The energy demands of Randonnée or Telemark skiers while climbing are identical. In my own research, it was shown that a 170-pound male skier burns approximately 785 kilocalories per hour when climbing full-time. This shows how more efficient Randonnée equipment is since the Randonnée gear was 35% heavier than the Telemark equipment! To get calories needed for Randonnée skiing multiply, in kilograms, body weight by .17 kilocalories per kilogram to get a kilocalorie-per-minute rate and then multiple that by 60 to get an hourly rate). Including resting, and climbing only 60 percent of the time, the figure totals 3,769.92 kilocalories in a eight-hour touring day (4.8 hours flat skiing and climbing). Factors such as skill level, slope angle, weather, and pack weight will further affect this figure (actually there are 30 variables). For comparison, a Tour de France cyclist may consume 6,000 kilocalories a day, while an Arctic skier may use 5,200 kilocalories a day.

For those scientists out there the following equation by Bigard (1987) and Vives (1996) shows the different components that account for total work being done during Randonnee skiing:

Wtotal = Wg (Wr2) + Wm + Wr1 + Wf +Wi
where:
Wg = work to displace center of gravity
Wm = work to accelerate and decelerate segment mass
Wr1 = work to overcome air resistance
Wr2 = work to overcome resistance of boots and bindings to forward movement
Wf = force needed to overcome snow resistance to sliding
Wi = work of internal metabolism