Possible Clues:

• Juice is full of it — that's a downer
• It keeps people grounded
• Force down sauce, swallowing it
• It causes objects to fall to the ground when dropped
• Extreme importance of the thing put into meaty juice
• Newton had a theory about it — this is serious!
• It’s gone in the sauce? That's a downer!
• Sex appeal in stock attractive influence
• It is covered in sauce — that's serious
• What's responsible for sinking? Something in boat's broken by it