Topic: Working out but not eating enough?

[like_a_child]

I'm just wondering, is there a level of exercise where the body actually needs more food, and Bad Things will begin to happen if your diet is not adjusted to support it? I have read that, when the body is not getting an optimum level of food, it begins to "strip out" the unneeded parts, and you become lean and stringy . . . but I was wondering where the breakpoint is that our metabolic efficiency can't keep up past, and what sort of Bad Things start to happen. Any warning signs that we aren't getting enough to eat?

Modification:
Okay, aside from the obvious of getting hungry

I'm good at taking my body to its limits, but part of that is suppressing the side effects and, more importantly, disregarding the lesser ones. I know when I'll fall over, but I don't know the intermediate stages very well; I don't know how serious any of them are. What sort of things would you be experiencing to get worried about the signals?

[Steven Low]

Long distance running. All of those guys are pretty much scrawny.

If you're losing muscle mass and you're not 200+ pounds at 4-8% body fat, you're probably not getting enough calories to support your lean muscle mass. That's pretty much the general "warning" sign. If you start losing weight and you have a low bodyfat, you're probably in trouble.

Unless you're working out for more than probably 2 hours (with weights) or running for more than an hour or two, you won't deplete all of the glycogen and fat stores in your body enough to the point where it starts metabolizing your muscles for fuel. Of course, metcon exercises make the process a lot faster so those are just pretty general times.

[like_a_child]

If you start losing weight and you have a low bodyfat, you're probably in trouble.

I just started looking up how to calculate bodyfat. Callipers . . . hydrostatic weighing . . . I think I'll just try to not lose weight, for now. No idea how I can manage that, though, I've been skinny for a long time and I never seem to gain any weight, no matter how much I eat.

[PrincessPK]

I believed the same thing until I started eating for real. Two years ago I thought I was doing all I could to put on weight and everybody was telling me how much I ate. One day I chose to really commit to a 6-meal per day plan and just stick to it. For two full months, I did not go up a single digit on the scale. Just as I was starting to give up, my weight starting changing and withing about 3-4 months I went from 138 to 150 lbs. I've always been naturally lean, and before that I was also very scrawny. Now I'm not anywhere near big, but my current muscle mass suits my needs and I don't want to increase it any further. You sound like you have a body type similar to mine, so accept the fact that your metabolism needs some time to ''gear in'' for weight gain before you actually start progressing. Just stick to whatever you're doing and let it happen.

Also, I tend to not lose weight even if I'm not eating too well for extended periods of time so I wouldn't worry about weight loss in your case. You can eat what you want and remain lean, but unless you're SEVERELY under eating for many months at a time I don't fear that you will lose much. If you do, it will simply be your muscles and liver losing some stored glycogen and not actual muscle going away.

[Matt Hudson]

Wow.
this was a very influential topic

[Jumpin Jiminy]

If you feel like you are getting sick or weak even hours after after eating a nutritious meal, maybe it wasn't enough food.  Check your vertical jump too and compare to your norm before working out.  If it is decreasing, either you are overtraining or you could be losing muscle mass.