Instead of using oil to sauté, you can use wine, broth, sherry, vinegar or even water, just some of it at a time. These substitutes help avoid the stickiness in the pan.
You can even use mushrooms as they produce a rich, dark, savoury broth that makes a perfect oil for garlic and onions, and adds an umami flavour that helps you keep salt out of the way too.
For baking, whole foods such as flaxseeds blended with water, soaked prune puree, canned pumpkin, applesauce, mashed bananas or avocado can be great substitutes for oil.