1)
Why did he discuss eating from spoils of the enemy?
1.
Malbim: The y would not lose time seeking food. The spoils of the enemy were ready in front of them!
2)
Why did he say "Ki Atah Lo Rabsah Makah ba'Pelishtim"?
1.
Rashi: This is in astonishment. Radak - surely, had the nation eaten, they would have had more than strength, and stricken the Pelishtim more! Malbim - even though they would lose a little time eating, they would gain and kill more Pelishtim.
