Foods That Cause Weight Loss

A negative-calorie food requires more energy to digest than the food provides in calories. Only about 10 percent of calories you eat throughout the day are used for metabolism and nutrient storage, according to MayoClinic.com. Eating negative calorie-foods, then, can theoretically contribute to weight loss by counteracting your caloric intake. However, definitive scientific studies are lacking.

Celery

Celery is a low-calorie food that is naturally fat-free, with low amounts of sodium and cholesterol, according to the U.S. Department of Agriculture Nutrient Data Laboratory. It is also a source of vitamins A and C, which are powerful antioxidants. One 4-inch stalk of celery contains only about 1 calorie. With the majority of celery being cellulose, which quickly passes through the digestive tract as insoluble fiber, very little nutritional value is garnered from this food. Celery does have high amounts of water that can help maintain hydration. In his book "The New Healing Herbs: The Classic Guide to Nature's Best Medicines," Michael Castleman writes that although celery's low caloric value can help an individual to lose weight in the short-term, the key to maintaining a healthy weight is a permanent low-fat, high-complex-carbohydrate diet and aerobic exercise.

Watermelon

A cup of sliced watermelon contains around 50 calories. It also provides an ample amount of vitamins, including C and A, according to Natalie Muth of the American Council on Exercise. Watermelon is a natural diuretic, which makes it useful for weight loss, Phyllis A. Balch writes in her book "Prescription for Dietary Wellness." Nutrients like fiber, calcium, iron, magnesium and B-complex vitamins contribute to watermelon's health benefits. Muth considers watermelon a negative-calorie food due its low caloric value coupled with its high water content.

Grapefruit

According to a 2006 study in the "Journal of Medicinal Food," grapefruit causes significant weight loss when eaten prior to meals. Additionally, fresh-cut grapefruit improves insulin resistance in individuals with metabolic syndrome. With only a mere 40 calories per medium grapefruit, this fruit is a negative-calorie food. It contains both soluble and insoluble fiber, which provide a sense of fulfillment while also regulating the digestive tract.