Board Thread:Manga/@comment-31940900-20160618204115/@comment-27441457-20160628040807

Manuel de la Fuente wrote: It could also be simply because Eren grew up. His original form is just a childish version of his later appearance. I point out again that Ymir's Titan didn't change in the slightest after eating Marcel. Growing up can't be a factor in the changing of Eren's Titan appearance, considering how the Armored and Colossal Titans didn't change between 845 and 850 (not counting Isayama's alterations of his art style).

From what I've noticed, the biggest change that occurs when a mindless Titan consumes a shifter is a change in muscle mass and tone.

For example, here's Frieda's mindless Titan:



In her mindless form, she's noticebly thin and emaciated, with her ribcage clearly visible from behind. However, after eating Uri, her form undergoes a slight transformation.



As a full-fledged Titan Shifter, her form now has bulked in toned muscle.

It's not really noticeable at a glance, but Ymir's form went through a similar change: thin with exposed ribs in her mindless form, and toned muscles in her Shifter form. Eren went through this transformation too, but to a much more extreme degree that I don't really know how to explain.