Maybe make it so that: The player character does NOT have to always order the same food as the girlfriend characters but can choose his/her diet independently?
Would that solve the problem?
Ps.: Generally i enjoy the whole fitness and weightloss struggle, so more of it in the game, not only for the player character, is always welcome!
Maybe even some upgrades that help with fitenss, like "fitness instructor"?
(i like to play with player wg off btw.)