I'm 45, 5'9 and have a 30-inch waist. How? I subsist on oatmeal, eggs, milk, fruits & veggies, peanut butter, cheese in moderation, TONS OF BLACK BEANS AND LENT

I'm 45, 5'9 and have a 30-inch waist. How? I subsist on oatmeal, eggs, milk, fruits & veggies, peanut butter, cheese in moderation, TONS OF BLACK BEANS AND LENTILS, rice, bread and pasta. Boring stuff. No meat. No soda. No fast food. Sweets and booze only on rare occasions. Black beans are good for your brain and leave you full & satiated for longer than most food. Their notorious side-effects -- to those around you -- are somewhat exaggerated. Fats and sweets make me feel lazy. I like to stay active (weights, hoops, doing things outside) but can slack for weeks at a time w/out consequence. I don't give myself credit for being disciplined -- just have good habits and decent genes. What I am proud of is that in spite of not being the most mentally healthy person, instead of turning to food or drugs to comfort myself, I use exercise, good food and a sense of humor to lift my spirits.