Tortoises are also fascinating to me, because they resemble a silent, slow dog with a hard shell. I love how big they can get and how long their lifespans tend to be - if cared for properly. The thing about tortoises that vastly differs between them and turtles - besides their obvious environment differences - is their diet.
A tortoises diet purely depends on their natural location from where they originated. For example, you wouldn't feed a Sulcata what you'd feed a Red-Footed tortoise, as it would not only process wrong within their bellies, but it wouldn't provide the necessary nutrients for them.

First off let's discuss the main diet of Yoda (our Red-Footed tortoise, see him HERE). He absolutely loves his fresh leafy greens along with the occasional fruit and veggie. The biggest thing to keep in mind though, is that fruit should be limited to about 1 or 2 times a week. The reason is because the tortoises don't need that much fruit (kind of like how we as humans should limit the amount of sweets we eat) and they can literally throw "fits" if their other meals don't include a piece of fruit.

Another big thing I learned is that while you can feed a forest tortoise food for a desert tortoise, you can't feed a desert tortoise food for a forest tortoise. Doesn't mean your forest tortoise will eat the desert tortoise food, but it's considered "safe". I found this out because after purchasing Yoda (see that post HERE) and receiving dry food that Yoda refused to eat, I looked into it and found out that he needed FOREST tortoise food. I was a bit agitated, but now that we've switched it I've seen a dramatic improvement in his diet.
Greens are great and forest tortoise food is awesome, but that's not all Yoda devours. In fact, his favorite dry food is a product called "Mazuri", which I couldn't find in any pet store. I ended up purchasing it through Amazon - which delivered it in 2 days.
Mazuri tortoise food is by far Yoda's FAVORITE, along with his greens and Tomatoes. It's renowned for being a love to tortoises, which I found out about on Instagram from fellow tortoise enthusiasts.
Something a lot of tortoise owners don't know - myself included - is that they do need a source of protein roughly about once a month. The reason they need is so little, is because it takes them longer to digest a protein source.

Overall it's important to feed your tortoise what their natural habitat would find and to give them their correct portions. If you need to add calcium or vitamins, you can also buy a powder to sprinkle on top of their dishes - without or without vitamin D - to help them maintain a strong healthy life. After all, you are what you eat.