Does swallowing your spit make you gain weight?

Answer 1

The majority of your saliva is made up of water. Although it may contribute to a slight increase in weight (less than 1 pound, I would say) temporarily, it would not affect your overall weight over a long period of time.

A couple reasons for this. First of all, the amount of saliva you intake probably accounts for less than 1% of your water weight (unsupported fact, would love to have clarification here). Second, the other 2% of the saliva are basically enzymes that help you break apart starch/fat and assist in the digestive process as stated above. Finally, none of the ingredients of saliva hold a significant calorie or fat content.

Basically, it would be like drinking water.