Water has no calories. Celery (with no dipping sauce) qualifies, because even though it does contain some calories, the effort of chewing it will burn more calories than the celery contains. Some diet sodas have zero calories.
There are low calorie foods such as lean cuts of meat, beans, and legumes are some of the high protein low calorie foods that would work good in a low calorie diet.
It depends on the type of food. Some foods are calorie dense while others are low calorie.
Everything. Calories are a myth.
Some examples of foods included in a negative calorie food list are celery, cucumber, lettuce, and grapefruit. These foods are believed to require more energy to digest than they provide, potentially resulting in a net calorie loss.
carboydrates, just not fatty foods, which increases bad cholesterol
LiveStrong has a list of low-calorie foods. They include greens, mushrooms, vegetables, fruits, rice cakes, popcorn, and things that are labeled as "reduced fat".
You can find the best foods for a 2000 calorie diets in books mostly. You can also find some articles about this diet in magazines and newspaper sometimes.
Foods
Zero calorie foods are good for someone who is on a diet and are counting calories. It really depends on the diet you are on. While zero calorie foods might be low in calories some are high in carbs. If you are on a low carb diet, such as South Beach, this might effect your diet and do the opposite.
Foods containing sucralose include diet sodas, sugar-free candies, and some low-calorie desserts.
calorie
You may find some of these negative calorie food chart at these sites. They are fasting.ygoy.com/2010/05/10/negative-calorie-foods-chart and www.fatfreekitchen.com/negative-calorie-foods.html