I don't know if you're familiar with Whole 30. It's an elimination diet where you don't eat soy, legumes, grains, dairy, sugar, or gluten for 30 days. (The answers to what you are probably thinking are "Meat, veggies, fruit, and fats" and "because I'm crazy.")
The actual answer is because my stomach is often having...troubles, and it seemed to be associated with eating. But short of logging everything I eat plus every symptom I have (booooring) it's hard to pin point what is upsetting my tummy. So the idea is that you eliminate the foods that cause inflammation/irritation and see your life improve, then re-introduce them one at a time to find your culprit. (I am not convinced that all of those foods are actually irritants, but obviously one of them was, because I feel much improved.)
You will find on the internet claims that it cures everything from infertility to eczema. I haven't quite seen that, but my digestive issues have abated, which is all I really wanted. Plus I've lost ten pounds in not even three weeks. Which isn't that hard when your snack options are fruits, nuts, beef jerky, hard boiled egg, etc. Not that I need to snack as much, though, because between the protein, fiber, and healthy fats I definitely don't get as hangry. I can tell when I'm actually hungry because, yeah, I'll take that apple and thank you for it. But when everyone else at the Grease Live! party is eating chocolate and you're having a Granny Smith, it's pretty sad. (Fear not, I claimed a handful of Ghiradelli squares and tucked them away for when this is over.)
It definitely has been a lot of prep work--there is basically nothing you can just grab and go, although I have been bending the rules with Lara Bars--but it's not actually hard. I miss cheese and bread and whatnot, but it's fine. I'm learning to like new foods (sweet potatoes...who knew?!) but because I'm used to everything being carb-based, it's been a big shift. And of course there's some monotony because I only like four meats, but dinner was feeling monotonous when I had the whole grain-based world available to me, so the problem may be more with me than with the options.
Anyway, it's not fun, but I would recommend it to people who have tummy troubles, an out of control sweet tooth (guilty!), want to eat less junk, etc. And while the stated intention of the program isn't weight loss (no calorie counting or macro balancing or anything!), pretty much everyone does lose weight on it, so it's a nice extra feature. I've also found that as I'm eating better I feel more motivated to exercise, which makes me want to eat healthier, etc., so it's a nice feedback loop.
All I'm saying is if I can do it, anyone can, so if you've been on the fence, I say go for it.