Does anyone know of anything safe to mix with tuna fish pre-contest that won't hamper my diet?

Mustard is good, there's different kinds that you can use, yellow, dijon, etc. Just check the label, some have sugars. Most are low or 0 cals.

walden farms makes great no cal bbq sauce, cocktail sauce and dressing. i find them in the low carb/atkins section.

I buy powdered wasabi (the green horseradish you put on sushi) and add soy sauce, balsamic vinegar, or water depending on my sodium allotment at the time. I call it "Michigan sushi". Be careful with the wasabi though, a little bit goes a LONG way!

You can buy tuna in these seasoned packs that also come with some pretty good reciped. The packs are anywhere from seasoned garlic tuna to lemon pepper. YUM.

I agre with the mustard and sweet relish. I have used it all through a diet when tuna boredom sets in. Its a personal choice as to the amounts...I put it sometimes on a piece of toasted whet bread.

If your diet calls for flax oil I like to mix a can of tuna 1 tbs. flax oil 1 tbs. cider vinigar mix all in 2 cups green leafy greens add 3 eggwhites.