> A thick desire is one that changes you in the process of pursuing it.
>
> A thin desire is one that doesn't.
>
> ...
>
> The person who checks their notifications is [a thin desire],
> afterward, exactly the same person who wanted to check their
> notifications five minutes ago.
[I added the brackets]
The author, I think, would label the desire for sugary drinks as a thin desire. However, that desire tends towards unfavorable consequences: mood swings, poor dental hygiene, weight gain. Thus it undermines one's body. This "changes you" -- for the worse, yielding a contradiction. If the preceding logical analysis is sound, the article's terms or argument are flawed.
The author, I think, would label the desire for sugary drinks as a thin desire. However, that desire tends towards unfavorable consequences: mood swings, poor dental hygiene, weight gain. Thus it undermines one's body. This "changes you" -- for the worse, yielding a contradiction. If the preceding logical analysis is sound, the article's terms or argument are flawed.