Restricting “bad” carbs is never a bad idea. I consider “bad“ carbs to include pretty much only sugar and high-fructose corn syrup. On most low-carb diet plans, you must also restrict your intake of "good" carbs, including fruit, whole grains and even many vegetables. Any diet that restricts a person's intake of healthy fruit and vegetables has to be a bit of a gimmick, in my eyes.
Most of the weight that a person loses on a low-carb diet is water-weight. This water-weight quickly comes back as soon as you eat a meal with carbohydrates. Many claim to lose 10 pounds in a week with the low-carb diet, but be assured, this is almost all water. Anyone looking to lose weight needs to lose fat. Losing water-weight may give you a satisfying number on the scale, but it has no long-term positive effects on your body.
This diet allows a person to eat unlimited quantities of butter, bacon and other high-fat, low-carb foods, which is just plain unhealthy. Low-carb fanatics will argue with this fact until they turn blue, but it is a simple truth. Eating hundreds of grams of saturated fat every day is unhealthy. Period. Especially for an already overweight person who has high cholesterol and other health conditions already.
Anyone looking to lose weight should increase their activity level and decrease their calorie intake. There is no quick fix to losing weight like the low-carb diet fanatics claim. What fun is living a life without eating bread or pasta ever, anyway?