The Science of Envelope Adhesive
Envelope adhesives that require moisture to be activated are primarily made from edible substances, most commonly gum arabic or cornstarch. Gum arabic, also known as acacia gum, is a natural product sourced from the hardened sap of acacia trees. It has been used for centuries in various food products, including candies like marshmallows and gumdrops, as well as in some beverages. Its non-toxic nature is why it is deemed safe for human contact and ingestion in such small quantities. Some modern envelopes use adhesives derived from cornstarch, which is also a common food ingredient and is gluten-free.
Are the calories significant?
The caloric value of these ingredients is very low, and the quantity of adhesive on a single envelope is extremely small. The amount transferred to your tongue during a typical lick is barely measurable. For example, the FDA noted that gum arabic contains about 1.7 calories per gram. A single lick is estimated to contain only about one-tenth of a calorie. Some older or foreign stamps may have slightly higher calorie counts, with British stamps reportedly containing between 5.9 and 14.5 calories per lick in the past. However, even these higher estimates are still insignificant from a nutritional perspective and most modern stamps are self-adhesive anyway. A person would need to lick tens of thousands of envelopes to consume enough calories to even register on a calorie-tracking app.
The Ingredients Behind the Stick
- Gum Arabic: Sourced from acacia trees, this is a centuries-old, natural food additive used as an emulsifier and thickener. It's safe and non-toxic for human consumption.
- Dextrin and Cornstarch: These are starchy compounds derived from corn or potatoes and are frequently used in modern envelope manufacturing, particularly in the United States. These are also non-toxic and gluten-free.
- Other Starch-based Adhesives: In some cases, envelopes may be sealed with glues made from tapioca, sago, or wheat, although cornstarch and gum arabic are most common. The risk of gluten exposure is low, but cornstarch-based alternatives are widely used and often explicitly noted as gluten-free.
Common vs. Self-Seal Adhesives
While the remoistenable adhesive is the subject of this discussion, it is important to distinguish it from the more common pressure-sensitive, self-seal envelopes now in widespread use. The glue on these envelopes does not require moisture and is not designed for human contact or ingestion. However, the glue used on self-seal varieties is still designed to be non-toxic, but licking is completely unnecessary.
The Calorie Comparison: Envelope Glue vs. Common Foods
To put the caloric content of envelope adhesive into perspective, consider how it stacks up against everyday food items. The differences highlight why the calories from licking envelopes are a non-issue for weight management.
| Item | Estimated Calories | Notes |
|---|---|---|
| One envelope lick (US standard) | approx. 0.1 calories | Based on gum arabic content. |
| One envelope lick (Older UK stamp) | approx. 5.9-14.5 calories | Higher estimates from older adhesives. |
| One grain of rice | approx. 1.3 calories | A tiny food item with a higher calorie count per unit. |
| One M&M candy | approx. 4 calories | Made with gum arabic, the same ingredient found in envelopes. |
| One teaspoon of sugar | approx. 16 calories | The amount of sugar in a single teaspoon is vastly more caloric. |
| One small piece of chewing gum | 2-5 calories | A common item, its calorie count is many times higher. |
Conclusion: More Myth Than Meal
The short answer to the question "do you gain calories from licking envelopes?" is technically yes, but the amount is so infinitesimally small that it is completely insignificant. The adhesive is made from common, low-calorie, and non-toxic food additives like gum arabic or cornstarch. A single lick provides a fraction of a calorie, making it a complete non-factor for anyone concerned with daily caloric intake. The myth of gaining weight from this action is unfounded, largely because the quantities involved are so small. If you're concerned about your health while mailing letters, using a moistening sponge or opting for a self-seal envelope is a simpler solution than worrying about the caloric cost of the adhesive.
Frequently Asked Questions
Is envelope glue safe to consume?
Yes, the remoistenable glue on standard envelopes is made from non-toxic, edible substances like gum arabic or cornstarch and is safe for human contact in the small amounts consumed when licking an envelope.
How many calories are in one envelope lick?
In the United States, an average envelope lick is estimated to contain about one-tenth of a calorie, which is an insignificant amount.
What is envelope glue made of?
Envelope glue is typically made from gum arabic (acacia tree sap) or various starches, such as corn or potato starch.
Does licking envelopes affect my diet?
No, the calories are so minuscule that they will not have any noticeable effect on diet, weight, or daily caloric intake.
Is envelope glue gluten-free?
In the U.S., the Envelope Manufacturers Association states that remoistenable adhesives are derived from cornstarch and do not contain wheat or rye gluten.
What about older or foreign stamps?
Historical or certain foreign stamps reportedly contained more calories, but these amounts are still insignificant. Most modern envelopes and stamps are now self-adhesive and don't need to be licked.
How do I avoid the calories and taste of envelope glue?
To avoid the calories and unpleasant taste altogether, you can use a damp sponge or cloth to moisten the adhesive, or simply opt for modern, self-adhesive envelopes.
