Thursday, January 13, 2011

Nutrition on the Trail - BMR and Calorie Intake

As a Nutrition and Food Science major, I can tell you first hand that the key to understanding nutrition is simple: eat plenty of fruits and vegetables, eat adequate fat and protein sources (keep trans fats out, and saturated fats low), and limit empty calories whenever possible (i.e. soda, sugary snacks). Backpacking nutrition is similar but just a bit different. As a backpacker, your energy expenditure and long treks will require much more calories, and especially foods that provide you with a quick burst of energy (aka carbohydrates).

Normally the average person (according to the USDA) has a diet of 50% carbohydrates, 30% fats, and 20% proteins.  My suggestion would be to lower the fat % just a bit, and increase the protein to 25% instead when gearing up for a hike. Protein builds muscle, therefore you do not want to deprive your body of the proteins you need to build muscle that will increase your fitness level and BMR. This will help you to increase strength and endurance for future hikes!

Your BMR (basal metabolic rate) is the amount of energy (calories) your body uses in a day just for regular functions (breathing, sleeping, etc). To calculate your BMR, you can visit this link, to get a general idea of what BMR to use. Keep in mind that this number can fluctuate based on your fitness level.

Because you are burning calories at a higher rate than normal (according to Livestrong.com, a 135lb backpacker burns about 590 calories per hour, when carrying a +/- 42lb pack) the amount of energy needed will be much higher.  This would mean that if you were to hike for 5 hours with limited breaks, you would burn approximately 2,950 calories. This is of course in addition to number of calories needed to sustain life, which you will determine by calculating your BMR

Therefore, if you plan on hiking 5 hours (burning 2,950 calories) and you need for example 1,650 calories to sustain life (BMR), you should plan on consuming at least 4,600 calories per day.

This may seem like a huge number, but I can guarantee that you will be snacking throughout the day to make up for lost calories. Also, be sure to drink PLENTY of water. Never wait until you are thirsty to drink. Of course, please keep in mind that when carrying a daypack you will burn fewer calories. This will also depend on the speed and intensity of your hike.

Feel free to visit this website for more information on calories burned while backpacking.

Until next time!

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