Lately I've been tracking my potassium intake so I can supplement correctly. Threads here and FITDAY show that there is potassium in the Tuna I eat but its not listed on the label of the can (the label only shows the amounts of Vit A, C, D and Iron). Should I just take FITDAY's word for the amount of potassium that is in the tuna I'm eating?

If you can I would call or email the company that packages the tuna. I have done that a lot and every company I have contacted is so helpful and cooperative. You will get more of an exact figure. I find when I add my custom items to FitDay with reading off of the labels of my food its much more accurate and it's never FitDay's total! I really think they have a general average in the food lists on the site.

I did email the company and I'm waiting for a reply. FITDAY is a great site but I do find that several of the things that I eat are not listed in the amounts or varieties listed there. One thing that I eat (once every two weeks) is a whole rack of ribs, dry or I'll go to the deli and get a 1lb of roast beef YUMMY, neither of which I can find on FITDAY's site. The roast beef is okay since I can get a label from the deli but the ribs are hard to track.

I also refer to the carb counter on the Atkins site. They have beef short ribs listed as a 6 oz serving:

Carbs: 0
Fiber: 0
Fat: 71.4
Protein: 36.7
Calories: 801!

Maybe you can use these calculations and see how many oz's you are eating.

Hope I helped!

Good luck and stay motivated!