It's always a good idea to load up the first couple weeks. Once it's in your system it will start working a lot quicker. Then from there you can lower the dose.
with reta the first 4 weeks can be the toughest. Once you get past 4 weeks it's usually much easier with side effects so I would start with a lower dose.
Just make sure if you're eating a lot of beans that you're also taking enzymes. A lot of times beans can be hard to digest. You'll end up with a stomach ache.