Recently I saw a podcast of Alex Honnold with Rich Roll where Alex speaks about deliberately eating up and gaining weight before going on an Antarctic expedition (I'm assuming this is because of the climate as well as his lack of body fat as a climber). Made me wonder if this is a tactic used by trekkers as well.

In case I'm going on long hikes (10 days or more), is it advisable to eat up and deliberately put on more weight before the treks? I'm a fit male who has very less fat percentage. Eating more to put on might be a way to offset the loss of weight that'll happen over longer treks.

Note: This is not a hypothetical question. I'll be hiking for around 2 months in the Himalayas and it'll be a long strenuous two months. I am expecting to lose some weight for sure. I'm wondering if I can offset this with some weight gain before I head off.


It depends on the circumstances, in fact people going for Mt. Everest will deliberately gain weight beforehand to offset the coming loss.



Also see one, two , three , and four other sources that say about the same thing.

As far as hiking goes, this is called "calorie debt" where instead of eating enough calories to maintain your weight, you are eating less and using body fat to make up the difference. This enables one to travel lighter since you are carrying less food and therefore less weight. The idea is that it's not a permanent thing but rather you replenish yourself from time to time along the way.

However, there is a point where adding extra weight to yourself makes you more slower and more liable to injury. Its also not possible to store up all of the weight needed for a two month trip.

According to Google, a pound of body fat has about 3,500 calories which is around how much a person burns in a day of hiking. So as a very, very rough estimate you could carry maybe 10 days of food in body fat depending on the person.

At the same time it is hard to replenish stored energy reserves and if you start depleting them, you will end up getting weaker instead of getting into better shape.

So this could be useful, but at the same time, one doesn't want to depend on it.

  • When you talk of Calorie debt, are you saying that body fat will act as your calorie intake and help one lose weight? But if one doesn't want to lose weight (due to lower body fat percentage), does it make sense to gain some weight (arguably a bad type of weight) beforehand? Also, I somehow feel that the answer implies that people hike to get fitter (correct me if I'm wrong). – Ricketyship Mar 29 '18 at 7:15
  • @Ricketyship Yes, in calorie debt your "intake" is coming from the stored reserves. It can make sense to gain some weight. People do hike to get fitter, but starving yourself isn't a great way to make that happen. – Charlie Brumbaugh Mar 29 '18 at 17:03
  • 3500 calories is at the very bottom end of what you would burn in a day of hiking. There are a lot of variables, including body weight, pack weight, distance covered and amount of ascent, but for most people 4500 - 6500 is a better estimate. – Tullochgorum Mar 30 '18 at 13:22

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