Vet said (fat) rat needs to lose some weight!

I've got a pretty chunky 1.5 year old lady who is....670 grams .

The vet suggested that I try to get her to lose weight but I'm not sure the best way to do this. I've read that cage layout really helps but I'm reluctant to remove the ramps because I fear she'll injure herself trying to get from one critter nation level to another.

I am going to stop free feeding my rats (They're all a bit hefty). How many rat blocks (Harlan Tekland) does a rat need per day? I've read that I can keep food out all together and just have food in their cage a few hours of the day, or remove it during their most active hours of the day.

Does anyone have any success getting their rats to lose weight? They don't seem to care for the running wheel in their cage, unfortunately. The vet said he hasn't seen rats intentionally lose weight for health reasons before.

You may want to hand each rat one block in the morning, and one block at night
But they will need to be fed a variety of vegetables ( broccoli, baby kale, mixed greens, cooked squash, cooked sweet potato, organic carrots (cooked or cut up), etc in the day and again in the evening. They will also need to be fed a cooked whole grain daily (perhaps at night time) as well - such as cooked real whole grain oatmeal or 12 grain cereal (good with blue berries), cooked quinoa (must be washed first - videos on youtube), cooked buckwheat, etc

With the exception of the rat block, do not feed any highly processed foods (rats should never be fed them anyway)
and stay away from seeds as they may put on weight.
Do not feed GMOs and try to feed organic when possible as if should have fewer pesticides, although organic from the USA and from China are not really organic.

There is info on diet and nutrition in the Reference Thread that would be helpful, https://www.ratshackforum.com/threads/reference-thread-read-only.35894/
such as this https://www.ratshackforum.com/threads/jorats-what-i-will-do-re-diet-posted-on-october-6-2018.36055/

The blocks will ensure they get the nutrition they need, the real food will give them lots of fibre, nutrition, and keep them full.
EDIT: Rats think the baby kale, peas, etc are treats - and really enjoy them !
…….. and rats should never be given anything that contains added sugar or sweeteners (feeds cancer), added fays, or added salt - processed foods contain these things

And they will need to get out to spend a lot of time running around and playing and interacting so that they get exercise and burn calories.

Jorats has spent years reading research on rat diets & nutrition and years ago she also had rats that needed to lose weight. She would be the best person I can think of to answer your question

Awesome! Thanks for the help.

As SQ says, cut out processed foods. Do the blocks as she said. For other food I give mine a supper, a variety of fresh veggies & cooked grains. When you make your supper put their veggies aside to add nothing to, and If you share rice or pasta dishes, wash off any sauces for them. No desserts. Give minimal treat by hand - I give 1 in the morning (a cheerio, froot loop, half a chex cereal or whatever cereal you have) and one at night (now they can have just a Tiny pinch of the cake or pie you had for dinner) - the taste gives them pleasure, the calories don't!
On your bed, or block off a section in your home, you can put varying objects there (small boxes, balls, whatever) for them to explore, they're curious, it encourages them to do some running around.