Just wanna point out that dietary fat is not the same as body fat. You aren’t made of walnuts, so walnut fat doesn’t go straight to your belly. Just about all fat gets digested and converted into sugar, put in your bloodstream, and then, if there’s excess, converted into body fat. To leave your body, it then gets converted back into sugar, gets used as energy, and then the CO2 goes back into your blood and exhaled.

Solid waste volume has surprisingly little to do with the actual food you eat. It’s primarily dead bacteria, 50-70% by volume. While some food makes it through, it’s mostly the nondigestable things full of fiber. And capsaicin.