Sims 4 Mod - Reverse Treadmill

Hey all,

I just finished my first ever Sims 4 mod - the Reverse Treadmill!

Instead of causing sims to lose weight, this custom treadmill (which is a clone of an existing model) causes sims who use it to gain! I set the rate of gain for the default “Reverse Workout” interaction to be twice as fast as the rate of loss for a normal treadmill, this can be modified with RoBurkey or by going into the mod file (just change the “commodity_fitness_fat” amount around line 233 in the reverse_treadmill_Workout file from 0.2 to whatever you like).

Pushing the limit causes an increase in the rate of gain, usually by around 50%. Some of the advanced interactions that are locked behind the fitness skill (endurance run, hill climb, etc.) also increase the gain rate significantly (as high as 0.5, or 0.7 for pushing the limit).

The treadmill still affects energy, fatigue, hygiene, and fitness skill normally. I considered adding a “fatness” counterpart skill to fitness but that’s way outside the scope of this project; perhaps some other time. Workouts on the treadmill also still count towards career progression for fitness-related jobs, so no more needing to overeat to compensate for your sim astronaut or soldier’s required workouts!

If you have any issues, questions or comments feel free to reach out below. I’m excited to hear what everyone thinks! If people want I would be willing to adjust the gain rate.

Download link: ReverseTreadmill v. 1.0


How do you create mods like this?

I used a program called Sims 4 Studio, there’s a whole forum dedicated to how it works and how to get started. Below are some links you can check out. I knew literally nothing about modding a week ago so it turns out it’s surprisingly accessible.

Here’s a site with free tutorials about the basics of modding for TS4:

Main forum for S4Studio:

Where to ask questions about specific projects if you’re having trouble:

Was also really helpful to use the S4Studio program to open up previous WG mods posted on the forum (especially the ones by @TheSimFattener) to get an idea of how to affect weight using mods (a super important number to remember is 16589, which is the tag for Sims’ weight stat).

Hopefully that should help get you started!


lame meme lol



I’m going to slap one of these into a variety of Fitness Centers in the game and see who just happens to jump on them. Probably throw it in my Main Sim’s house and do some experiments with her. See how the treadmill works with my Roburky settings (which I cannot remember off the top of my head).

I like the sound of a Fatness stat or something like you’ve mentioned above. I imagine it would be very complex (I have no experience with modding of any kind), but I’ve always wished your Sim’s bodies/general fitness mattered more in these games. Like the level of Fat your Sim had could effect how easy working out is for them. Maybe even how a Sim views themselves? Maybe a fitness nut would hate being fat, a gainer may enjoy it, or potentially just not really care. Again I imagine it’d probably be very difficult to make any mods relating to this.

I may check out the guides you’ve posted above and maybe try to teach myself some very basic stuff. First time posting on this site, but I’m a long time lurker lol. I hope my wall of text here is on topic enough. Not exactly a person who talks much/posts on forums often.


Looks cool, I am hyped to try it out. I am so glad others are finally starting to make their own sims 4 mods


Honestly if it wasn’t for the amazing work you’ve done I wouldn’t be playing the Sims and I never would have made this mod. Would be super stoked to collab sometime if you have the capacity :smiley:

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That’s hilarious! And hot as hell!

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I have been super busy in life which has slowed down my mod making progress, I have a few random testing features in play, but if you would ever wanna share some ideas feel free to let me know!

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Yeah will do, I’m working on a list of stuff I want to try out!

I just realized, why isn’t there a stuffing mod? Like being able to fill a second hunger bar(over the first one, like an overfill), and the sim’s belly gets bigger the fuller the bar is?

It may be difficult or impossible to add another need bar, and you’d have to do custom animations to make the belly stuff, which I wouldn’t be able to do.

Well, i know, there is a vore-mod made from the modder bees123.
The prey sim is swallowed and the predator sims belly swells of the max. size of the chosen kirax´s bellyslider. When the swallowed sim is digested, the swollen belly slowly shrinks back to normal size. I think, you can change the effect into “slowly inflate by eating more food than needed”.

…i have a feeling, that was very bad english; sorry for this XD

I’m not the biggest fan of inflation/stuffing myself, and I’d still probably need some good animation skills to make something like this work, so it probably isn’t for me, unfortunately. There may be others in the community who have the skills necessary to do this, though.

Does anybody have any other ideas for existing objects that could be modified to cause weight gain? Would be interested to hear people’s ideas, they could inspire another similar mod.

Ah, you mean something like a cursed mirror, that adds 20 pounds, every time a sim is using it or a wishingwell wish-option to become the “greatest sim of all time”?

Yeah exactly! I’ve also got a few other ideas but I’m wondering if I can get some more from the community.

I can place the treadmill but I can’t seem to be able to have a sim interact with it in any way or click on it.

Im not quite sure what’s going on. If a sim is too tired to use the treadmill it will show the options but greyed out. If they are energized I can’t event select it.

Do you use the Sims in another language besides English? I just realized I forgot to update the string table so that may be causing the problem. If the string table isn’t updated it works for the English version but if the game is set to run in any other language it will get grayed out options and not be able to use it.

Here is a link to a new version that may help with your problem: