Gary Heavin, founder and CEO of Curves International, observes that some women do well on a particular diet, while other women on the same diet not only don't lose weight, but actually gain weight. He attributes this to varied metabolisms and because some women are carbohydrate-sensitive and others are calorie-sensitive.
Carb-sensitive women are more than 25 pounds overweight, have been overweight most of their lives, often skip meals and crave starchy or sugary foods.
In general, calorie-sensitive women are less than 25 pounds overweight, didn't have weight problems when they were younger, but have slowly gained weight since turning 30, have a normal appetite and few food cravings.
Some women have identifying factors in each group. Heavin recommends that these women start by watching carbs, and if they do not lose weight after two weeks, they should switch to a calorie-sensitive diet.
If results are not seen after trying both approaches, Heavin says these women's metabolism may need a period of recovery before they can lose weight. More information is available in his book Curves (Perigee).