2 year old drinks ~2 gallons of milk per week. could this be reason for light/clay colored bowel movements?

Clay colored stools can indicate an absorption problem, sometimes a nutritional deficiency or a problem with the liver or gallbladder- all of which would be odd to see suddenly show up in a child, and especially one with no other complaints or symptoms. This one would probably be best to ask the pediatrician about. He may ask for a stool sample to be done, and give him a good routine lookover, just to be safe. It may be nothing at all, except something to give you a few extra grey hairs. But have the doctor look to be safe.

Please contact your pediatrician. I would not trust the health of my child to a bunch of strangers on yahoo! That's a lot of milk for a toddler! I can't imagine how this little one is getting a balanced diet and drinking all that milk without getting obese. Nutritional deficiencies or imbalances at such a young age can cause a lifetime of health problems.

Yes, or some bread or carbohydrate food he is eating. You are so right to watch his bowels.

Here is an article that may help you more

Bowel Movements Indicate Your Overall Health

Yes - it can cause light-colored stool. But more importantly, he is drinking more milk than what is healthy for him. Too much milk can cause anemia as it doesn't allow his body to absorb the iron he needs to make blood. It is really important to limit his milk intake; don't give it to him until after he eats, when he is more full. Otherwise, just water (avoid juices - too much sugar) or water with sugar-free flavoring.

TWO GALLONS?!

Yes, probably. The light coloured stool will be from excess calcium.

Make sure he doesn't drink as much! Try replacing it with juice or water.

Of course. What goes in, comes out. Nothing is wrong with your child. Give him more meat and vegetables- the color will change.

yes,most definatly!try and cut down milk consumption and replace with fruit juice or good old water