I use my fitday.com to calculate how much I'm eating. I don't worry about portion size as much as I do to make sure I'm getting 10-12x my weight in calories (which by the way I'm not since I'm not hungry) and that my carbs stay below 20 (14 today after fiber subtracted) and that 70% of my calories come from fat. I figure if I stay at those ratios I'm following this WOE pretty well. My meat portion is usually 6+ounces, once you get used to this -and I've only been doing it for a week- you pretty much know what adds carbs and what doesn't. I feel pretty safe with how I'm doing this.