There is no exact answer to this question. In my “The Best Backpacking Food – simple and nutritious”, I threw out the best guess of 1.4 to 1.7 lb of food per day. But how but much food you need depends on who you are and what you do.
2015 Note: In the last 15 years of backpacking I personally seem to have settled on around 1.7 pounds per day of food give or take a bit. This is for warm season backpacking with 12-18 miles per day (possibly more) with some off-trail travel. If I am going for killer trips, like 10-12 solid hours of hiking per day I will be more like 1.8 pounds of food per day. But trips 12 miles and under, mostly on trail 1.5 pounds of food would suffice.
Over the years I have lowered my hiking pace, but hike longer and take fewer breaks. I find that a slower hiking pace of 2.5 miles per hour (average including stops) is much more efficient calorie-wise than hiking at a faster pace. Most accomplished long distance thru-hikers I have talked to use a similar approach. Also, I find the slower pace beats up my body less and I get up the next morning fresh and ready to hike another day.
Estimating How Much Food You Need
In an example below, in order to not lose weight, a 160 pound male hiking 10 miles a day, with a 3,000 elevation gain, would need around 4,000 calories per day, or 2.0 pounds of food per day (assuming a caloric density of 125 calories per ounce). This is a very rough estimate, and should not be taken too seriously. You will need to do some experimenting to determine you own caloric needs for on the trail.
From this it is clear that 1.5 pounds of food per day (a figure often used by ultralight hikers) does not work for all situations, and for all people. Although that 1.5 lb of food per day may work well for many people on a short trip (e.g. a 3-day-weekend)–where they not doing long miles and long hours of hiking per day. And for most of us, if you end up metabolizing/burning off a pound of fat on a trip [since backpacking is one of he supreme fat burning activities], all the better!
But just because you can get by on 1.5 lb of food per day, doesn’t mean that it’s the best way to eat in all situations. In my opinion, running a significant caloric deficit, particularly on longer trips, is not a good idea. If you are a fit person, hiking many miles and hours per day, 1.5 lbs of food per day is also not a good idea. See my example below for more details.
Factors to consider for how much food you pack
- How much do you weigh?
- Does your metabolism run high or low?
- How far will you hike each day?
- How fast will you hike?
- For how many days?
- How much elevation gain?
- At what altitude?
- At what temperatures?
- How difficult is the terrain?
- What type of shape are you in?
- What are you used to eating?
- How much excess body fat do you have?
- Do you want to lose weight? Etc., etc.
In 2000 I took 1.6 lb of food per day (Approx. 125 cal/oz.) on a 5 day trip in the Rockies. I was hungry on the days when I hiked 8-10 miles mostly on trails. But I could deal with it. I would have felt better, and in the long run hiked faster with more food per day. One day, I did an 18 mile hike, most of which was off trail, with elevations over 13,000 feet. Boulder fields. Class 3 routes etc. I brought only 1.6 pounds of food with me. By 7:30 PM, when I got into camp, I was almost psychotic with hunger. My fault, I realize. I could have easily used 2 lb of food for that day.
An (over) simplified example of food need calculations. An estimate! (see Note 1):
- A 160 lb person has a base metabolism of approx. 2,200 cal/day
- 10 miles hiking with a 30 lb backpack at 120 cal/mi, is another 1,200 calories.
- Assume 3,000 elevation gain is another 600 calories.
- Total caloric expenditure: 4,000 cal/day
- 1.5 pounds of food at 125 cal/oz = 3,000 calories. (see Note 2)
- Caloric deficit = 1,000 cal/per day. Or around 1/3 lb of hiker per day (this is fat metabolized/burned)
Under this very simplified estimate, our 160 pound hiker runs a 1,000 calorie per day deficit. They would lose about 1/3 lb per day or around 2 lb per week. If our hiker was a bit overweight and didn’t mind being hungry this might be OK or even desirable. But it’s probable that they would feel better and hike faster if they weren’t running a caloric deficit.
For someone near their ideal weight, running a 1,000 calorie a day deficit might not be a good idea. It might be OK for a few days, but not for long outings. It’s not that you can’t do it if you have to. I’ve hiked 3 days without food. But is it a good idea to hike running a caloric deficit?
- Is it good for your health?
- Will you feel great and enjoy your outing?
- Will you hike your fastest?
- Will your body have the nutrition to recover after a hard day of hiking?
- Will you be more injury prone?
- Will you be alert and make safe decisions?
- What will your moods be like around others?
After answering these questions for myself, I’d say that hiking with a daily calorie deficit is not a great idea.
Note 1: I realize that this is a this very simplified estimate. Base metabolism, hiking efficiency, etc. are variable. The best approach is to do some on or off trail testing and see what caloric intake works best for you. Note that you may be able to get by on a low calorie intake but your athletic performance may go down as well. I know that I can eat 2,200 calories a day and ride my bike 175-200 miles per week. I also know that if I do this, I feel terrible, I loose around 2 lb per week, I can be cross with those around me, and my overall riding speed drops 1-2 mph. At around 3,200-3,500 calories a day I feel great, don’t gain weight, and can train at high intensity.
Note 2: I believe that most of us will end up averaging around 125-130 cal/oz even when packing high fat items like chocolate and peanut butter, etc. as part of our food. I know that many try to hit the 150 cal/oz range, but I don’t think this is a realistic or healthy way for most people to eat. Just my opinion.