I was just wondering, because it was suggested by someonen at another fitness forum that a 3oo pound woman eat 300 to 450 grams of protein to lose weight .
Protein is very acid-forming (especially animal protein, but too much veggie protein can be as well), which throws off your body chemistry and causes your body to either not absorb some alkaline minerals (like calcium) that are used to form bone, or to actually leach those minerals from the bone. It can also be hard on the kidneys, that have to work overtime to rid the body of the excess protein.
Andrew Weil states that excess protein is harmful to the immune system.
In studies on protein balance, it's been very hard to find a diet that is too low in protein, unless it is unbalanced (junk food, lots of processed foods, or high in citrus fruits).
Aiming for about 1 gm. of protein per KILOGRAM of body weight (1 km. = 2.2 pounds, so a little less than half your body weight in protein) or as much as 1 gm. per pound of body weight (though that may be an unnecessary amount) is a good range.