Tallywell.

Popcorn (air-popped) vs Potato chips

Both count toward 30 plants a week.

Popcorn (air-popped)Potato chips
Protein · per 100 g12.9 g6.6 g
Fiber · per 100 g14.5 g4.8 g
Energy · per 100 g387 kcal536 kcal
Protein · per 100 kcal3.3 g1.2 g
To hit 30 g protein233 g · 900 kcal455 g · 2436 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.