Before listening to the latest offering from Fattburger, one might wonder at the deeper irony of the title -All Natural Ingredients (Shanachie 5026 46:12)-for a band so heavily steeped in synthesizer effects. There may very well be some self-effacing mockery to it, because other than a few washy, keyboard heavy tunes (ie: “The Grip”), Natural is somewhat dressed-down, and more groove-driven than the Fattburger norm. Part of the reason is lately-added guitarist Evan Marks, who makes his presence felt on a slick cover of “Everybody Wants to Rule the World” (a perfect match for the band’s wide-open sound) and the cheery “Lo-Cal Swing,” -but there are other treats, too. Hollis Gentry contributes soulful flute to the sprightly Tito Puente classic “Oye Como Va” and Carl Evans adds a driving piano solo to “So Far So What.” “Coronado” finds Gentry mixing it up on sax and flute through a multi-dimensional urban feel setting. Though the steps are measured (don’t fret, Fattburger fans), it’s gratifying to hear an established band scale back and explore the basics a bit.