If you dig a little deeper you’ll find that methylcellulose has some interesting culinary properties, making it well suited to adding structure and firm texture

If you dig a little deeper you’ll find that methylcellulose has some interesting culinary properties, making it well suited to adding structure and firm texture to soft foods. When mixed with water it transforms into a firm gel after heating, or it can be used to create extremely resilient emulsifications. It’s practically flavourless, so it works well. I’m not convinced it passes through the GI tract with no impact whatsoever, but it appears so far to be relatively benign. It’s nothing like sawdust or a filler, though. It’s also somewhat expensive so it wouldn’t be a good option for filler. My 500g bag was around $25, but if you wanted to use actual sawdust, well I think you could get that for close to nothing.