Nope, no conspiracy. Just food companies trying to cater to the age old law of supply and demand, as well as "adding value" and creating the demand themselves. It's no different than any other corporation, really. A company's job is to do right by its shareholders or owners, so they throw stuff at the wall and see what sticks, then if it sticks, they keep doing it. Or if a trend is snowballing (high fat, low fat, low carb, etc), they'll jump into the snowball in an effort to get new business and stay competitive against their rivals. To me it's just the nature of business, not a big conspiracy.