I'm currently trying to do VLC but am confused as to why there is a sweeping "one size fits all" recommendation. For instance, around "30 grams" is thrown around on here and on various blogs as low-carb. But is this for everyone? Should it be even less for me? I've had 26 grams already today, but I'm wondering if it is too much.
I'm a fairly short woman (5'4"), and I imagine that my VLC daily carb intake should look different than someone who is say, a 6'5" bodybuilder taking in more calories than me.
Your brain requires 120 g/day of glucose. If you're in ketosis, then the daily glucose need is reduced to about 30 g because the brain can use ketone bodies as fuel. The remaining 30 g glucose requirement can be manufactured from either glycerol (fat) or amino acids (protein). If you eat both VLC and low protein, your body will begin breaking down your muscles for fuel.
I think the "30 g of carbohydrates per day" guideline is intended to be high enough to prevent muscle wasting (since gluoconeogenesis from protein stops somewhere between 15-50 grams/day) but low enough to force the liver to create ketone bodies (which will start at anything under 100 g/day). And it's the same guideline for everyone because your brain is the only organ that requires glucose, and human brain sizes are pretty much the same, regardless of height or weight.
The very best advice anyone can give you is to keep reading and keep an open mind. There is a good deal of conflicting information and the Paleo/Primal/PHD world is young and changing rapidly.
Personally, I don't recommend you count carbs (or anything). When I want to lose weight, I ditch starch all together. I eat meat and veggies.. all I want. I also eat eggs and some dairy (but dairy can cause other issues for some people).
If you are VERY active, you might need some starch even while trying to lose weight. Personally, I don't think being VERY active is a great way to lose weight.
Context always applies.
Why are you trying to limit your carbs? is it for weight loss? I am recently recovering from a knee surgery and as such cant do any soccer, walking or running. I had been consuming between 250 - 400 carbs a day (I was fairly active, weights 3 times a week, soccer 2-3 times a week) mainly in the form or potato and rice. I feared I was going to have to change my ratios in order to keep the weight off while being more sedentary. Not the case at all. I haven't changed a thing and am actually leaner than ever. This jives with CaveDad's response that being very active isn't the most ideal way to lose weight.