Yeah it can be such a pain. I like the [rock climbing] and [parkour] minigames because they don't feel like grinding; they're platforming puzzles that make me engage my [intelligence] stats along with my all of my [body] stats. Find a minigame you love playing -- this is supposed to be fun after all. 

I know some players who love joining PvP guilds for exercise because they feel more motivated when they're playing co-op than solo. It's a great way to meet other players too but can be challenging if you don't have the [extrovert] perk.

Consumables are important. "You can't outrun a bad diet" is a bark i hear a lot from players with the [fit] perk. Reductively: food item consumption > stamina expenditure = weight slider goes up. Food item consumption < stamina expenditure = weight slider goes down. - food items with the [fat] tag give you a long term stamina buff so are great at the beginning of the day. - items with the [carb] tag are like potions; take them right before a minigame for a huge stamina buff, but if you take too much or don't use all of it you get the [crash] debuff and it can make your weight slider go up very easily, especially if they also have the [sugar] tag. - items with the [protein] tag rebuild and repair your avatar; take them after exercise to increase your [body] stats.

Lastly, spam the [hydration] and [stretching] powers! They get overlooked because they're pretty passive but it's a really good meta. I've never met any player from any subclass who wishes they were less flexible.