On the Core Phase, you have two basic dieting options: the Classic Plan or the Flex Plan.Classic Plan
Actual food items are described in the following pages. Only certain kinds of proteins, vegetables, fruits and starches are allowed.
For either plan, the main rule is that you can only have one from each food group in any given meal. For example, you cannot eat all the proteins at the same time (same meal), or all the starches at the same time, etc. This rule basically means each meal naturally includes more than one food group. It also means for the Classic Plan you'll tend to eat 2 meals per day (one item from each group per meal), and on the Flex Plan, 3 meals per day. However there is some flexibility as we'll show later in the Core Phase Daily Schedule section.
Historically, most participants have been able to stick with the Classic Plan (the original program) and tend to lose the most weight. However, there is some evidence that the higher protein amounts and calories in the Flex Plan will produce equal weight loss for some people while also assisting with retaining lean body mass. Everyone has a slightly different metabolism, different lifestyle, and different needs. The important thing is to settle on a plan you can stick with for the duration of the Core Phase while achieving the weight loss you are happy with.
If you can't decide which plan to start with, consider the Flex Plan first. You can always switch plans later. If you aren't losing much weight on the Flex Plan, maybe you should be more restrictive and try the Classic Plan. (Or try a blend of the two. See the "Diet Adjustment" for troubleshooting and advice on adjusting the plan.)
Keep a daily record of your food choices and serving sizes. As long as you follow the serving guidelines in this section, you don't need to worry about counting calories. The serving suggestions in the diet plan have been designed to automatically provide the right number of calories.
However, if you want to count calories, you are welcome to do so. The Classic Plan should provide close to 500 calories per day, while the Flex Plan should provide between 900 and 1,100 calories.