The number was 10.
Almost immediately after Katie swallowed the fruit, her whole body began to tingle. "Uh Tiff. I am feeling really strange right now" Tiff just looked at her friend and nodded as she could see that something was going on.
Katie first started to shrink. Her height dropped fast until she had lost 9 inches, bringing her back to the same height she was before puberty. Next she watched as her small B-cup breast deflated into nothing but a flat chest. Also, all her hair was going a bit crazy. While the hair on top her head began to arrange itself into a style Katie had from an earlier age, her pubic hair completely receded leaving her bald and puffy. Finally her face grew younger and younger until Katie looked just like she did when she was 10.
"Well" Katie started with a voice she hadn't heard in a few years, "I guess we know what this fruit does now." And with that, the majority of her cloths, now to big for her, fell off leaving her in nothing but her shirt. All Tiff could do was stare. She had just watched her friend regress back to the age of 10, and was now wondering just what these fruits were capable of....