You may not be able to go a day without coffee but there are many ways to cut down on calories in your coffee. Coffee is naturally low in calories but when we add the milk and sugar the calories increase.

Switch to low fat milk. Milk adds a lot of taste to coffee but can be high in fat for low fat or non-dairy creamiers are a much lighter option.
Change your sugar out for splenda. Splenda has no sugar in it which can cause a spike in your blood sugar and increase insulin levels.
Cinnamon is a great way to add flavor without a lot of calories. Cinammon goes great with milk.
Add a sugar free syrup. A lot fo coffee shops offer sugar free verisons of their most popular syrups that can add some great taste to your coffee.

The healthiest way to enjoy coffee is in its natural state but these tips can make it tasty for less calories.