Beans and other dry pulses are excellent.
I usually buy dry black beans, rehydrate them over the night and then cook them until they start falling apart. I have a pressure cooker so that takes around 30 min, but it takes 2 hours or so without pressure.
Next, I fry some bacon in my skillet. Fry until crispy and set aside. Fry onions and other favourite vegetables in the bacon fat, carefully lift veggies letting the fat drip back into the pan.
Throw beans into skillet, add some good quality oil and lots of spices. Make beans properly mashed, they absorb fat like sponges if you smash them open. The fiber in the beans and veggies helps negate any known negative effect of the bacon.
I always buy my vegetables at chinese grocers, everything is cheap as hell. You just need to keep your wits about you and not buy shit you have no idea how to cook.