conspiracy theory

I really am not a numbers person. I really don't get IT. I got through high school math ok, but college algebra kicked my butt. I'm not a dumb person, but when number get involved my brain makes weird turns and angles. It doesn't make linear lines (Did I just make some math jokes?) So..today I'm thinking about food...which is normal on any given day, and I start to think... How does anyone really know how many calories are in anything? Then I really start to think, maybe it is all a commercial ploy. No one used to count calories. Now you have food, diets, all kinds of things that focus on calories. I mean really can someone explain to me how you calculate one slice of lasagna equaling 1 million calories? <-----This is an example of a hyperbole - extreme exaggeration to make a point. I mean I imagine they have a calorie institute somewhere where people are eating and then getting on treadmills and then the input is divided by the output and written up about in The Science Of Calories tri monthly journal or something. Wow....sorry this has gotten way out of hand. Anyway, my point is that I think it is all in our heads. I think if we believe that slice of cheesecake is going to make us fat it will. If we don't think it maybe it won't. The mind is a powerful thing!!! Wow...I sound like Pollyanna again. So what do you think....have we been brainwashed about calories?