Laziness and sleepiness are so similar that there must be another reason than being lazy or tired. It's constipation.
People need to get a good diet that includes probiotics, so that they stay regular. One help is black seed oil... nigela sativa... black cumin oil. It fights the parasites in the body so that probiotics can work easier.

Perhaps we need to understand what is the case of their laziness or being tired. For me, I remembered back then when I was too tired even without activity and when I check with my physician I'm in borderline diabetes.
So diet and exercise and I didn't take that much carbs and some meds. I'm still a type-2 though, but I know the signs and will have to take some drastic actions of my blood sugar rose.