Coffee stands in one of those cloudy areas when it comes to "harmful or helpful?" My personal opinion goes back to my motto - find your balance. If you're drinking a pot of coffee (or more) everyday, you're at risk for harming your body. However, I think up to 3 cups per day can actually be beneficial to your health.
Studies have found coffee to reduce the risk of heart disease, stroke, diabetes and
infections. Additionally, it maybe linked to decreasing your chance of Alzheimer's disease, dementia, Parkinson's disease and other diseases... even cancer.
Coffee has a ton of antioxidants like polyphenols that work to inhibit oxidation that leads to damaged cells and diseases!
Don't go overboard though - Too much coffee can cause irritability, increased blood pressure, GI distress, even fibrocystic breast disease. Don't wear out your poor adrenal glands - we need our hormones!
So where does the real problem lie? The real problem is what we put IN our coffee. So many people add cream and sugar, so basically sugar on sugar.. and lots of it! Try to taper that back overtime by using only one and reducing the amount. Eventually, switch to unsweetened almond or coconut milk.. or even black if you can! We want to enjoy the coffee, not develop diabetes from all the added sugar!
Drink smart :)