Some people have to worry about portion size and some people do not. I have found that I have to carefully monitor my portions in order to lose weight and this has become more of an issue the longer I have been on Atkins (it has taken me almost 17 months to lose the 99 pounds I have lost so far). However, I don't monitor portion size by weighing or measuring; instead, I have learned to carefully monitor myself and stop eating the second I am not hungry. In order to do this, I have had to slow down my eating so that I really think about what I am eating and really think about whether or not I want another bite because I am hungry or because it tastes good and is fulfilling some need other than hunger. When I am hungry between meals, I drink a large glass of water and do something distracting. If I continue to be hungry, I eat, but often I find the between meal hunger goes away without eating. I have also found that regular, moderate exercise (walking at 3.5 or 4 mph, or swimming laps) helps to regulate my hunger and going for a walk often solves the between meals hunger issue for me. However, more intense exercise seems to make me more hungry and I end up increasing my calories beyond the point where the increased exercise does any good with regard to weight loss.