roommates only making sweets

@amygamie& @goldann25 I have had this also, at least in some of the cases.  I've played several different Save Games and one of them (in one of the dorms) didn't have this problem (equal amount of real food and sweets) , another dorm only made sweets, another dorm started out with regular food and then switched to only sweets, and finally in one of the hosues that is considered University Housing, my Sim's roommates only bring sweets.  

Here is how I got around being overweight .  If you have the Cool Kitchen Stuff Pack then you can set up the ice-cream maker without using cheats at the Student Commons.  (Larry's Lagoon, or Darby's Den). And if your cooking skill is high enough you can make the "Taste of Diet" ice-cream and eat a serving or 2 depending on how much weight you need to loose. 🙌 You don't need to use the Freebuild cheat in the Student Commons and all purchases in Build/Buy are free ! 
You can also use the Freebuild cheat in the dorms or student housing if you don't want to travel to the Student Commons, but the items will cost your Sim money.

Also, if you have enough Aspriation Reward points, you can go in the Rewards Store panel and purchase a weight loss potion (I forget the name) .  Just beware that it will make your Sim really skinny! 😮

You can also exercise but this is really hard to do without a gym on campus .  You can use the Freebuild cheats and put a gym in the dorm, but exercising requires a lot of time to loose weight. 

Also, it isn't just sweets that pack on the pounds; dishes like lobster thermidor are very fattening!  And that is one dish that dormmates love to bring to share! 🤨

Here is Carl's Sims 4 Guide explaining how the food , exercise, and weight gain/loss works in the game.https://www.carls-sims-4-guide.com/tutorials/calories.php