Think about the amount of caffeine you are drinking in coffee, tea, colas and energy drinks. They will cause a similar roller coaster effect to sugar and cause the release of the stress hormones, adrenaline and cortisol.
They are classed as stimulants. Because they can cause a drop in blood sugar, they can also trigger either sugar cravings or an increase in appetite in general. Also, when you are changing habits there may be some that are natural stable-mates, such as tea and biscuits, or coffee and a chocolate bar.
So it can be easier to break a habit by breaking the association. If you are not having the cup of coffee, you might not think about having the chocolate bar.