I'm not sure if that article is entirely correct. Eating greater than 30% protein won't throw you into ketosis nor is a high protein diet "ketogenic". A ketogenic diet is about 75% fat and any excess protein will throw you out of ketosis via gluconeogenisis. I like 0.8-0.9 grams of protein per pound of body weight. I'm about 123 pounds and like at least 90-100 grams of protein per day to feel satisfied although some days can be as low as in the 60's, the next day I'm seem to want to eat a whole roasted chicken! My protein is about 25-30% of my caloric intake but I don't feel as well when it gets over 30%.