The reason Hashem created us with physical needs which take away time from serving Him:
The Baal Shem Tov taught: Every spiritual existence desires to attach itself to G-d through learning Torah and Avodas Hashem. Now, if the person would have a constant passion and excitement in attachment to G-d, he would become nullified in existence. Therefore, Hashem arranged that one must dedicate himself for some time each day towards his physical needs, such as eating, drinking, and making a living. Through one taking a break from his Avodas Hashem during this time, the soul gets to rest and the intellect is allowed to strengthen, in order so he can return to serving Hashem afterwards.
 Tzafnaas Paneiach Bo 33; Keser Shem Tov 178