Even meticulous calorie counters need not worry about licking a single stamp. However, anyone who licks hundreds of stamps or envelopes should be concerned.

 

When a stamp is licked, some of the glue used is absorbed through the tongue. This glue contains energy value. The amount of calories absorbed in this way depends on the composition of the glue.

The adhesive on envelopes and stamps consists of polyvinyl alcohol and dextrin. Dextrin is usually made from potato starch, vinyl alcohol from petroleum.
Depending on the amount of glue used and its composition, the glue in a stamp can contain between one and 15 calories. The average amount of calories is 5.9 calories.

In 1995, Englishman Dean Gould made history by licking 450 stamps and sticking them on envelopes within four minutes. If you calculate the total calorie intake with an average of 5.9 calories per stamp, Gould consumed the incredible amount of 2655 calories in just four minutes.