While there are multiple versions of this diet, they all, for the most part, tell the dieter to eat and drink food products that have a negative caloric effect. A "negative caloric effect" means that the number of calories your body has to expend to chew, digest, metabolize and eliminate the food is more than it gains from the food itself. A classic example of a negative calorie food would be celery, which is made primarily of water and cellulose (fiber that your body can't digest), and non-caloric vitamins and minerals.

Negative calorie fruits and vegetables

Different versions of this diet allow different specific foods, but they are all generally fibrous vegetables and fruits such as: asparagus, lettuce, broccoli, green cabbage, carrots, cauliflower, apples, blueberries, cantaloupes, and cranberries. The diets claim that you can eat "all you want" of these selected fruits and vegetables and still achieve drastic weight loss.

Weight loss potential of negative calorie diets

The negative calorie diet claims that weight loss of up to two pounds daily is achievable. Even if this were true, weight loss this drastic would never be recommended to anyone who is not under the strict supervision of a physician. A generally accepted rate for healthy, sustainable weight loss is considerably slower - 1 to 1.5 pounds per week. Any success that a person would have while following the negative calorie diet would be due to drastically reduced calorie intake. Also, depending on the version of the negative calorie diet that you read about, it should be noted that a diet consisting only of fibrous fruits and vegetables is not healthy over an extended period of time, as it will not include enough protein or essential fats.

Eating the amount of fruits and vegetables recommended by the U.S. National Institute of Health—5 servings a day for women, 9 for men—could cause weight loss in and of itself. Fruits and vegetables are good food choices because they contain large amounts of water and fiber, along with important vitamins and minerals. The large volume of non-caloric water and fiber in these foods can make you physically full—it physically pushes out on your stomach, which will often end hunger pangs.

Negative Calorie Diets are Too Much of a Good Thing

However, the negative calorie diet is a case of a good thing taken to an extreme. Fibrous fruits and vegetables are a very important part of a healthy diet, but are not a healthy diet in and of themselves. Look for more sensible alternatives that include a broad range of nutrient-dense foods from a variety of sources, in sensible quantities.

	Hello? You need food to live. Your car doesn't run on negative gas does it? This is a starvation diet disguised as a high fiber diet. If you want a high fiber diet, try the aptly named High Fiber Diet or the Mayo Clinic Diet. More on these diets below...

High Fiber Diet

This diet focuses on foods high in fiber. The diet is intended to fill users up without making them gain weight. The high-fiber diet is said to stabilize blood sugar, lower cancer risk and control the appetite. As users will discover, this diet can contain much more than bland oatmeal and other grain. A large variety of healthy and delicious foods are high in fiber, and this diet attempts to highlight them.

Mayo Clinic Plan

The Mayo Clinic Plan offers a lifestyle approach to managing your weight and maintaining it. The plan lets you eat virtually unlimited vegetables and fruits, plus a variety of healthy choices from all of the food groups. It can help lower high blood pressure and cholesterol, as well as reduce your risk for heart disease, type 2 diabetes and certain types of cancer. Mayo Clinic experts have developed this plan to help you live a longer, healthier life. Each food group recommends healthy choices for optimum results. Daily physical activity is at the center of the pyramid because of its positive effects on weight management and overall health.