This 'bulking up with air' is most evident if you go to the yogurt or cream cheese section and look for the Yoplait Whips or Philadelphia Whipped containers. It's the same product, just as a foam, and seems to be marketed as a healthier alternative where users choose a satisfactory portion by volume, not by calories or weight.

And while I think the whipped foods are stupid, I don't think that packaged food sellers are necessarily scumbags. They're merely people responding to incentives, just like everyone else. The food market has razor-thin margins and consumers are ill-informed. Neither consumers (who are hard to inform) nor regulators (who are captive to the multinational conglomerates) have been able to push back more strongly than the profit incentive, so the so dark patterns like those you describe are inevitable.