Dr. Brewer recommends 80-100 g of protein/day, and he's considered by many to be out in left field (too much protein). I'd be interested in where she heard "half your body weight" in protein, because that doesn't scale well. For someone who's 120 lbs, 60 grams isn't going to be too much, but for someone who's 220, 110 is a lot. And for someone closer to 300, that becomes practically impossible.
I've heard the same recommendation (half your body weight) in ounces for water consumption per day. And I have the same problem with that recommendation. For an average weight person it seems fairly reasonable. For an overweight person it no longer is.