Understanding the Purpose Eating & Oneg Shabbos

From B'yam Darkecha on the Beauty of Shabbos & the Yomim Tovim: R Yossi Michalowicz by R Yossi Michalowicz.

pp. 397 - 406 : The concept of "Separating the Sparks" which happens when eating during the weekdays, which is not necessary or desirable on Shabbos. Why we should eat less during the weekdays, but eat more on Shabbos.