How long should I wait after eating to brush my teeth and put back in my invisalign trays?

The issue isn't the food debris on your teeth. The issue is having plaque on your teeth. Plaque is population of bacteria. When you eat, the bacteria eat also. They will give off nasty substances such as acids and endotoxins. It is these substances that are deleterious to your teeth and gums. If you feed these bacteria they will give off these substances for up to 240 minutes after you have eaten. It is found that if you chew sugarless chewing gum after a meal, you cut the acid production down to 20 minutes. This is because it stimulates salivary production.Saliva has two different buffering systems in it that buffers the acids plus it offers a dilutional effect that helps with the concentrations of acids and endotoxins. Add to this that the chewing gum has a plunging effect to "stir the pot!"

That being said, you cannot chew chewing gum with your aligners in. I recommend to my patients that they take a few mouthfuls of water and swish 3 or 4 times before placing the aligner back in the help wash away all the food debris and dilute acids and sugars in the mouth. When you have an opportunity to brush later, seize the opportunity!

Dear danb12:
There is no set guideline as far as how long you should wait.  However, use common sense.  Unless you are sitting down for a ten course meal everyday, eating is fairly quick and takes about 15 minutes.  Give your body a chance to digest the food in your mouth and then go ahead and brush your teeth.  Make sure to rinse your mouth first with water so as to remove all food particles.  Then, go ahead, brush and insert the trays.
Most importantly is to ask your dentist when you come in to check the progress whether you are doing a good job brushing.  The at is a major step that people forget.
Best of luck,