A message posted on BodyBuilding.com forum -a website dedicated to body builders in United States- indicates the concerns of a 33 year old man about the amount of protein alleged to U.S. tuna cans label and the actual amount inside.  Full text below:

Regular 6 oz. can of tuna ONLY YIELDS approx. 3 oz. of drained tuna!!!

Why does a normal 6 oz. can of albacore tuna say it contains approximately 2.5 servings of drained tuna at 2 oz. PER SERVING? In other words, the can says it yields 5 oz. of tuna (2.5 servings x 2 oz.) once it's drained.

Why the macros on the can are completely wrong:

1. Weight of entire, unopened can of tuna = 7 1/8 oz.

2. Weight of entire empty can (just the bottom and lid) = 1 1/8 oz.

So right there, that leaves us with 6 oz. of tuna AND water combined.

Well, then we have to DRAIN the water from the tuna, and I can tell you right now, that there's A LOT MORE than just 1 oz. of water in a can of tuna.

I've had 4 cans of tuna over the last 2 days (Chicken of the Sea Albacore & Bumble Bee Albacore) and the weight of each completely drained can has been the following:

Can #1 - 3 1/2 oz.
Can #2 - 3 1/8 oz.
Can #3 - 3 1/8 oz.
Can #4 - 3 1/4 oz.

Yes, I drain my tuna thoroughly, but I don't use any special devices, I simply press the lid down on it firmly until all the water is gone and then weigh it on a digital scale. As you can see, my average can of tuna has yielded NOWHERE CLOSE to 5 oz. of solid tuna, like the can says it does.

So, using 3 1/4 oz. as the average weight of my last 4 cans, these are the macros we're looking at:

1 can of drained tuna (approx. 3 1/4 oz. OR 1.625 servings @ 2 oz. per serving):

114 Calories: 1.6g F, 0g C, 24.4g P


But if you were to simply go off the can, you'd think your macros were:

175 Calories: 2.5g F, 0g C, 37.5g P

The point here isn't so much about the difference in calories, but overstating your protein consumption. The can makes you think you're getting about 38g of protein in each can, when in reality, you're only getting about 24g. If you're watching your macros carefully, this is important, as it adds up quickly over the course of time, especially if you eat a lot of tuna.

Has anyone else noticed this?