Rika-san will get to the meat of her presentation after the coffee break.
A similar phrase is meat and potatoes. Like the main course of a meal, the meat and potatoes are the fundamental but indispensable parts of a project or job.
Gravy
The profit
We still have to deduct the shipping costs, but the rest is gravy.
Gravy is a type of sauce used on meat and potatoes.
Trim the fat
Reduce the unnecessary expenses
Ito-san has to trim the fat before he presents the sales budget to his boss.
Watered-down
Weakened or milder
Takeda-san gave a watered-down version of his conference speech to the office staff today.
Icing on the cake
The additional bonus, the unexpected additional good news
Reiko-san had expected the year-end bonus, but the icing on the cake was the additional holiday week her boss granted.