It’s called a negative-calorie diet. At its simplest form, you eat food that your body spends more energy chewing and digesting than the food actually produces.
The best known negative-calorie food is celery. You could eat celery day in and day out and never gain weight. Other examples are asparagus, watermelon, pineapple, grape fruit and papaya. In fact, you could eat almost all fruits and vegetable as negative-calories foods as long as you eat the whole thing (not just the juice).
Thanks for the information on cholesterol and hypertension – much appreciated.