Tallywell.

Pretzels (hard) vs Popcorn (air-popped)

Both count toward 30 plants a week.

Pretzels (hard)Popcorn (air-popped)
Protein · per 100 g10.0 g12.9 g
Fiber · per 100 g3.0 g14.5 g
Energy · per 100 g384 kcal387 kcal
Protein · per 100 kcal2.6 g3.3 g
To hit 30 g protein300 g · 1152 kcal233 g · 900 kcal

Bold marks the better side of each row. "Per 100 kcal" answers the density question — which food delivers more protein for the energy it costs. Portion row is computed live from the same USDA base values shown on each food page.