Here's how many calories you're really eating for lunch

Chain restaurants in New York (and soon across the country) are required to display them, and although calorie counts are not the best measure for people trying to lose weight, they're one of the easiest ways to track how much you eat.

But how reliable are all those numbers?

Tech Insider's Kevin Reilly brought popular meals to Columbia University's Department of Medicine to find out, filming their bomb calorimeter as it calculated the exact number of calories in Big Macs, Chipotle burritos, and more. (Spoiler alert: There's a blender involved.)

Then he compared the results with what the restaurants had posted, and found that many of the official counts were way off.

Keep reading to see how your favorite chain stacked up (we saved those with the biggest discrepancies for last) and what the companies' responses to these findings were.