Guar gum can best be described as a natural food thickener, similar to locust bean gum, cornstarch or tapioca flour. It is said to have significantly more thickening ability than cornstarch, at a fraction of the cost. This has made it a popular additive in products such as puddings and ice creams. Until recently, it was also an ingredient in non-prescription diet pills designed to create a sense of fullness.
The guar plant, also known as a cluster plant, grows primarily in Pakistan and the northern regions of India. It thrives on the drought/monsoon cycles present in those areas. The plants are harvested after the monsoon season and the seeds are allowed to dry in the sun. The seeds are then manually or mechanically separated and processed into a flour or sold as split seeds. Guar gum is an important cash crop for the Indian and Pakistani economies.
While consumers may balk at such "exotic" ingredients as locust bean gum, carageenan and guar gum, the truth is many ice creams, puddings, and canned sauces would be fairly inedible without them. Guar gum is not just a thickening agent, but a binder and plasticizer as well. When untreated ice cream melts and refreezes, grainy ice crystals often form. This substance has the natural ability to bind with water molecules, preventing them from forming the unwanted crystals. Processed foods with creamy textures are primarily held together with binders such as this. Without a binder, the individual ingredients might separate into a watery mess.
The use of guar gum as an ingredient in non-prescription diet aids was officially banned in the early 1990s by the FDA. It would bind with liquids in the stomach and swell, causing a feeling of satisfying fullness. This swollen mass could also cause dangerous intestinal and duodenal blockages, however. Guar gum was declared unsafe and ineffective for use as a non-prescription diet aid, although it is still used in small amounts as a food thickener and binder.