Negative calorie foods

I was eating some fresh (not canned) pineapple this morning at my desk and thought to myself ~I wonder if there's a diet made up of ONLY pineapple..I could eat ony pineapple if I had to!~ and I found it. Pineapple, ice water, and tuna (?!) I'm not sure I'd really enjoy tuna and pineapple for a week straight but that's just me. On and off the raw food wagon for months, I'm hoping to get inspired again and figure out my happy medium.
So this morning, I had..

1 banana

1 Odwalla Strawberry/Bananna juice

1 1/2 cups fresh pineapple

I love fresh fruit. LOVE IT! So maybe I can do this pineapple thing..or something similar. I've put on 16 lbs in the last 5 or 6 months and I'm I misserable. My clothes fit and I'm sure it's not all fat as I'm skating a lot now (Roller Derby) but still..16 pounds! Here goes nothing..again!

I found this list of "Negative Calorie Foods", where your body actually burns more calories than they contain. That's kind of a cool thought..

Negative Calorie Vegetables
Asparagus
Beet Root
Broccoli
Cabbage
Carrot
Cauliflower
CeleryChicory
Hot Chili
Cucumber
Garden cress
Garlic
Green Beans
Lettuce
Onion
Radish
Spinach
Turnip
Zucchini

Negative Calorie Fruits
Apple
Blueberries
Cantaloupe
Cranberry
Grapefruit Honeydew
Lemon/Lime
Mango
Orange
Papaya
PeachPineapple
Raspberry
Strawberry
Tomato
Tangerine
Turnip
Watermelon