I'm now in maintenance, so I'm basically following my own program, so to speak. However, it is built on a framework taught by the health management clinic I used for weight-loss: Health Management Resources. It's a nationwide group of hospital-affiliated clinics. The core of their non-medically-supervised programs is something called Healthy Solutions, and it is based on years of research and studies that show that the following are postive contributors to weight-loss and weight-loss maintenance:
Healthy Solutions has two modes: "In the Box" days, and "In the Bigger Box" days. "In the Box" days require three meal replacement shakes (like EAS Myoplex Lite), two meal replacement entrees (like Lean Cuisine), and five large servings of fruits and vegetables (preferable three cups of lightly prepared vegetables, and two whole fruits [or similar amount, for large fruit like melons]). 3-2-5. These are MINIMUMS. You also can have a couple of snack replacement bars if you wish, but it isn't essential.
"In the Bigger Box" days aren't really any "official" part of Healthy Solutions, but once folks get into Maintenance they rarely do "In the Box" days -- I only do them once every few months to reinforce to myself that I still have that level of control over my eating when I want to. "In the Bigger Box" basically translates the meal replacement imperative into "three servings of lean protein." Also, certain vegetables that aren't necessarily recommended on "In the Box" days are allowed, like popcorn. Some people also expand their "Box" to include a limited amount of other low-calorie snacks.
Regardles of the "Box" the calorie balancing principle still applies: Calories In minus Calories Out is still kept in check.
So, in a nutshell, Healthy Solutions is a lot like Weight Watchers' Points system (although it is a bit older), in that you track calories (or Points, which roughly represent a certain number of calories), and you should also track numbers of servings of various types of nutritious foods.