Energy comes from food, and the fast way to get energy from food is through carbohydrates.
Coffee is a stimulant. It might improve mental clarity but there's no energy in it whatsoever. All that other stuff just helps you utilize your energy stores better. That is, if you're deficient.
Originally Posted by
matimeo
I stay about 15 pounds overweight and find that it keeps me from bonking on longer rides. A little bit of built in storage gives me energy for days.
And yeah, supplements are all gimmicks and marketing. You're wasting your money and better off focusing on good nutrition. I eliminate almost all refined sugars from my diet, and that helps a lot as well.
Someone already pointed out that supplements are effective when used properly, i.e. as "supplements."