Half the fun of going to the movie theatre, for many people, is the popcorn. It's salty, buttery and nothing like the air-popped or microwavable version at home.

While most of us know the snack isn't exactly health food, you might be surprised at just how much fat and calories are in some movie popcorn.

CTV News, along with The Globe and Mail, commissioned independent lab Gelda Scientific to analyze samples of large popcorn from three concession stands at the biggest movie theatre chains, with and without buttery topping.

What we found was that on average, the large popcorn -- without the topping -- had a staggering 1,100 calories, 60 grams of fat and 1,235 milligrams of sodium.

That's about the calorie and fat equivalent of two of KFC's infamous Double Down sandwiches.

Throw on that topping and you've got a few more calories -- 1,261 -- and an astounding 79 grams of fat along with 1,300 milligrams of sodium.

To put that into perspective: the average adult should aim for 2,000 calories a day or less, and should take in no more than 65 grams of fat and 1,500 milligrams of sodium per day. That one large bag of movie popcorn might come pretty close to hitting those quotas -- exceeding them in fact in the fat department, while offering almost no nutrition.

Most movie goers likely don't know how many calories they're taking in with those popcorn combos, because theatres don't post the nutritional information of their snacks on their menu boards or their websites.

But we asked each of the big movie chains to provide us with the nutrition facts for their popcorn. Cineplex Odeon and Empire Theatres offered us that info; AMC didn't return our calls.

The numbers provided by both Cineplex and Empire for the fat, calorie and sodium content in their popcorn were much lower than our test results. When we tested a large, no-topping popcorn, we found:

Cineplex Odeon

• 1,141 calories
• 67 g fat
• 1,128 mg sodium
• Cineplex said a large popcorn had 850 calories, 40.5 g fat and 399 mg sodium

Empire Theatres

• 1,116 calories
• 51 g fat
• 1,695 mg sodium
• Empire said it had 637 calories, 28.5 g fat and 1,297 mg sodium

AMC

• 1,060 calories
• 62.6 g fat
• 883 mg sodium
• The company didn't provide us with their own nutritional information

As for why there were such discrepancies, the serving sizes we picked up at the theatres were larger than the ones the companies used in their testing. Both companies also blamed human error for inconsistent methods used to prepare the popcorn.

When the same large bags of popcorn were analyzed with buttered topping, the calories jumped to 1,400:

Cineplex Odeon

• 1,420 calories
• 100 g fat
• 1,095 mg sodium

Empire Theatres

• 1,225 calories
• 67 g fat
• 2,114 mg sodium

AMC

• 1,138 calories
• 69 g fat
• 694 mg sodium

While the numbers aren't good for movie theatre popcorn, the theatre chains say they are planning some changes.

Cineplex Odeon says it expects to launch soon a new popping salt that's 50 per cent lower in sodium. And they say they're now using a new canola oil-based popping oil that reduces the overall fat content and the trans fat compared to their previous popping oil. They call the oil Vegetol Cineplex Popping Oil, and is now in use in all of their theatres in Canada.

Empire Theatres says it has invested heavily in the development of its "Popcorn Program" to deliver a consistent product at all theatres.