* BMI measures weight relative to height. For adults, a normal BMI is 18.5 to 24.9; overweight is 25 to 29.9; and obesity is 30 or greater. BMI is calculated as weight (in kilograms) divided by the square of height (in meters). See alwayshungrybook.com for a BMI calculator.

* There is no simple way to determine what proportion of obesity is genetic compared to environmental in origin. And even if there were, that number would differ among populations and through time. For a society in which most people eat healthy diets, the few cases of obesity that did exist would be mostly related to genes. But for a society in which many eat poorly, the opposite would apply (and the United States is closer to this extreme).

* Unpublished results, with permission from Iris Shai.

* I recommend that you discuss participation in the program with your health care provider before getting started, especially if you have any medical problems. This would also be a good time to request baseline laboratory tests, if you plan to do them.

* To break up the big first shopping trip later in the week (see here) into two, consider purchasing nonperishable items on Day -4 or Day -3—especially if you’re shopping for a big family.

* If you’re already at an optimal body weight and chose to follow this program for health benefits, your set point won’t change.

* Nutrient data are approximations and will vary to some degree according to the specific products used.

1 Glycemic load describes how a food (meal or entire diet) affects blood sugar for several hours after eating. Frequent consumption of high–glycemic load foods is strongly linked to excessive weight gain and risk for heart disease and diabetes, as discussed in chapter 4. The glycemic load is determined by multiplying the glycemic index of a food with the amount of carbohydrate present in that food. For a comprehensive listing of glycemic index and glycemic load, see www.glycemicindex.com.

2 The values used to classify glycemic load vary somewhat between food groups in this table, to allow for better discrimination of foods within groups.