Malbim: [Even if they have grain] if they lack tree fruits, and need to buy from Goyim around them, it will seem that there is hunger, and they will have shame from Goyim due to this.

Radak: Eretz Yisrael needs rain more than other lands. Therefore, hunger is more common in it than in other lands. Avraham, Yitzchak and Elimelech testify to this. When one goes from his land to another land due to hunger, this is shame.