Tallywell.

Flax seeds vs Chia seeds

Both count toward 30 plants a week.

Flax seedsChia seeds
Protein · per 100 g18.3 g16.5 g
Fiber · per 100 g27.3 g34.4 g
Energy · per 100 g534 kcal486 kcal
Protein · per 100 kcal3.4 g3.4 g
To hit 30 g protein164 g · 875 kcal182 g · 884 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.