"Added fillers" refers to unnecessary or extra materials that are included to fill up something, often with the intention of making it appear larger, fuller, or more substantial than it actually is. Full definition
We use only fresh ingredients in our products and do not add any fillers, preservatives or junk. (organicmania.com)
I have been making green smoothies for a while now but I never thought to try adding a filler like you suggested of oats or quinoa but I will be trying it this weekend! (greenthickies.com)
Either make your own coconut milk or select a BPA - free brand that is unsweetened and does not contain added fillers and chemicals. (bembu.com)