The narrator describes a character who appears fit and attractive, characterized by being "lithe and tanned." However, there's a sense of loss in his authenticity, suggesting that while he seems appealing on the outside, something essential is missing. This quality gives him a somewhat artificial aura, as if he were a manufactured version of what he should be.
The comparison to orange soda implies that although he may provide immediate satisfaction, there is a lingering bitterness that suggests underlying flaws. The synthetic nature of his appearance raises concerns about health and substance, ultimately leading the narrator to question the value of such superficial qualities in a relationship.