Every food commercial, advertisement, and packaging in the US is currently protein obsessed. I just bought 3 burritos, and the most noticeable thing on the entire package is its protein content. TV commercials about waffles are advertising that they have X amount of protein per serving. The products in my jobsite's vending machine have protein all over every package.
Protein takes longer to metabolize into energy than carbs, hence you don't crash like with carbs. Starchy veggies give you carbs, low-carb veggies don't have protein or carbs so you'll just be extra tired.