If one doesn't eat much, but still moves a lot, what's the lower limit before it becomes dangerous? Does anyone know?

do you mean I drink too much water, or too little, or if I drink enough water, it won't matter how much I eat?

???? Lower limit of what? Do you mean, what is the lower limit of Calorie intake?

Basal metabolism Calorie requirements vary with body type. The rule used to be that an average American had a basal metabolism requirement of 1600 Cal/day; now, it's probably more. Above that, and you need more Cal to sustain exercise... or so goes the theory.

However, I often go on 3-4 day trips when I don't feel that hungry, and probably eat no more than 2000 Cal/day, when the altitude gain says I should be getting more like 5000 Cal/day.

In the 1970s, it was estimated that the Chinese (mainland) averaged about 1400 Cal/day, even though they typically had manual-labor-intensive jobs.

No idea but as long as you have energy, I think you should be fine. Keeping hydrated is obviously important.

Can't the human body go without food for something like 40ish days?

If you are talking in general (not just hiking/climbing), the quality of the food will be more important than the quantity.

I'm talking in general. People comment on how little I eat... so I started to think it's maybe unhealthy to not eat more.
Right now I'm at a level of eating around 950 calories a day - and I'm not dieting. I counted a few days, to check how much it added up to. It just doesn't add up to more. Once a month I have a hamburger and a coke, otherwise I think I eat pretty healthy. Mostly.

40 days, huh... well, that'd be starvation.

The average American, it depends on if it's a man or a woman, I guess. Guys eat more. 2000 isn't a much for a man, for me, it would be a lot.

and yes, I meant in calories.

Lolli wrote:I'm talking in general. People comment on how little I eat... so I started to think it's maybe unhealthy to not eat more.
Right now I'm at a level of eating around 950 calories a day - and I'm not dieting. I counted a few days, to check how much it added up to. It just doesn't add up to more. Once a month I have a hamburger and a coke, otherwise I think I eat pretty healthy. Mostly.

40 days, huh... well, that'd be starvation.

If your weight doesn't change and you don't get sick, then that's perhaps what is right for you. However, if you eat too little your body may think it is starving and lower its metabolism rate accordingly. Then if you eat more, it starts storing the "extra" as fat. You also lose muscle, not a good thing if you want to do things.

I eat about 1600-1700 calories when I want to lose weight and 1900-2000 to maintain. I am 168 cm tall and weigh 61 - 62 kg. I'd like to get it under 60.

I have no medical experience and my theory of food is loosely based off of a few studies I've read, personal experience, and wishful thinking.

There is an organ similar to your brain that is connected to your digestive system. When you eat something your body records what nutrients are in it and banks that in the old gut memory. Your body knows whether it needs more nutrients and what kinds, hence your hunger for certain amounts of certain things. Following this theory, I try not to let my brain worry too much about what I eat, instead letting my stomach do the nutritional calculations. Following this logic, I usually eat somewhere between 2000 and 4000 calories a day depending on my activity. I eat as much as I am hungry for of whatever it is I feel like. If 950 calories is what you're hungry for, then (by my logic) that's probably how much you should be eating.

If I'm hungry, I eat more. Periods I eat more. (I like that theory, drpw)

What Moni says is more worrisome, of course I don't want to lose muscle. Does one do that even if one is training and hiking? I have to watch out for that. I believe I have a slow metabolism, this isn't exactly the first time I eaten like this for long periods.

drpw wrote:I have no medical experience and my theory of food is loosely based off of a few studies I've read, personal experience, and wishful thinking.

There is an organ similar to your brain that is connected to your digestive system. When you eat something your body records what nutrients are in it and banks that in the old gut memory. Your body knows whether it needs more nutrients and what kinds, hence your hunger for certain amounts of certain things. Following this theory, I try not to let my brain worry too much about what I eat, instead letting my stomach do the nutritional calculations. Following this logic, I usually eat somewhere between 2000 and 4000 calories a day depending on my activity. I eat as much as I am hungry for of whatever it is I feel like. If 950 calories is what you're hungry for, then (by my logic) that's probably how much you should be eating.

If I followed that regimen, I'd look like the Good Year blimp - I LOVE to eat and have to really watch how much I eat.

drpw wrote:When you eat something your body records what nutrients are in it and banks that in the old gut memory.

I've read something along those lines as well. According to the article I read, that is one of many reasons that diet soda (and other artificially sweetened) foods are bad for dieting. They screw up your body's natural response to sweet foods by training your body that sweets don't contain calories.

950 calories is probably a bit lean for someone who is active (on a day in and day out basis). To get an unbiased opinion talk to a doctor in a physical (they have your physical well being in mind and not your looks or your perceived physical performance). If (s)he says that your body mass is fine for your body type its a good starting point.

Then see if your body weight is dropping or if you are chronically getting injuries or illnesses, or if you feel like you are dragging through workouts or you just don't have the power, then you are probably running a bit light on your calorie intake. Listen to what your body is telling you and not what your head is.

I say perceived physical performance since carrying extra mass will result in physical performance (I'm talking about outdoors and not indoor evening activities) decline but being underweight will result in an even more rapid decline in performance. That side of the coin is lost on a lot of distance runners and climbers.

Now for short periods of times I have gone lower, like zero calories taken in for upto 5 days when climbing trips took longer then expected. But I have to say it usually messes up my metabolism for a month or 2 afterwords.

When I remember, I drink a big glass of milk now and then, to up it.
Can't say I lead a very healthy life overall, but so far, touch wood, I'm rarely sick.

There is a body of medical literature pointing to the proposition that significant calorie restriction (I would say under a thousand calories for most adults is significant) increases longevity. However, most people, especially in fast food nations like the US of A, could come nowhere near tolerating such calorie restriction. Naturally, great calorie restriction will limit the physical activity you can do comfortably or at all. No Iron Man triathlons on 950 calories per day!

It's on the lower end but if you feel energetic enough, I doubt it should be a problem.

I also don't think I would worry about losing muscle as long as you stay active.

I think the people that lose muscle are the ones that starve themselves to lose weight but don't do any activity whatsoever. IMO, that's the completely wrong approach. Exercise > diet.

I'm not sure what my calorie intake is but during the week, I usually have a piece of toast in the morning, a turkey sandwich at lunch and soup at night.

I do like to pig out on the weekends though ... but I'm a lot more active then.