Thursday, October 14, 2010
Over the past couple of weeks, visits to the supermarket have become a study in nutritional science as I juggle the competing parameters of my food requirements for my upcoming hiking expedition.
* As I will be out there for 32 days, I have to ensure a balanced and complete diet with what I eat – I can’t afford to run myself down. (On my last hike, I did hit the point where I had depleted my body’s glycogen stores, fortunately I was able to drop in on a shop for a 1000 calorie instant sugar hit – this time I won’t have that luxury)
* Walking 12-18 miles a day carrying a heavy pack over a rugged terrain, I figure I will be burning about 2500 exercise calories per day, or a total of 4500 calories per day.
* 10-12 days between resupply points means everything has to be non-perishable
* Having to physically carry everything means that it has to be lightweight (and relatively compact) – I am aiming at a pound and a half of food per day. It will probably mean a pretty heavy pack as I start out each time, but I’ll probably be flying towards the end of each stage.
* For much of the route, campfires are prohibited, so food has to be quick and easy to cook to minimize the amount of stove fuel I have to carry.
This has had me carefully scrutinizing nutrition labels, entering foods on spreadsheets to compare nutrients against total weight, and getting enough trace minerals and vitamins – in short becoming totally obsessive about food. And keeping things from being monotonous for 32 days means I have to find several different daily menus that meet the above criteria, rather than just a single solution.
Carbs are the logical source of energy for this level of activity, but the reality of trying to shoe-horn 4500 calories into a pound and a half means a significant intake of fat in my diet (carbs and protein both have 4 calories per gram, while fat has 9 calories per gram). This is something I feel vaguely uncomfortable with, as I have tried to follow a low-fat diet ever since my father had heart bypass surgery 20 years ago. But the realities of the situation mean I have little alternative – I’m just trying to go with as many healthy fats as I can.
Identifying lightweight non-perishable protein sources has been a particular challenge. While powdered milk is an obvious starting point, getting in 100-150 grams of protein in milk alone is simply not feasible, so powdered eggs for breakfast are definitely on the menu. A few small tins of salmon and tuna will also probably go in my pack. I also need to look at some dried (but easy to cook) bean options.
Another challenge is just consuming 4500 calories per day (harder than it sounds). At this stage, I am looking at 1250 calories for breakfast and dinner, 750 calories for lunch (generally uncooked), and another 1250 calories in snacks throughout the day. Snacks in particular are going to have to be a mix of complex and simple carbs to keep a good flow of energy throughout the day – home made trail mix, here we come.
I’m figuring on buying about half of my resupply requirements (the more mainstream items) at 2 ski resorts the trail passes through on the way, and mailing myself some packages of the harder-to-obtain dehydrated and speciality items, to be collected from local post offices.
I’m just really appreciative of the tools, and the knowledge and understanding that Spark has given me to be fully aware of my nutritional needs. If I had tried doing this expedition before I had discovered Spark, I could really have got myself into trouble.