Perhaps the most important aspect of the king sago palm is its use as a food source. Despite its toxins, products made from the king sago palm have been consumed for many years. It is mainly used by the poorer people of the southern Japanese islands. This is because starch can be extracted from the seeds and pith of the tree in surprisingly large amounts (nearly 30% of the seed can be solely starch), resulting in a fairly cheap source of food. This starch, called sago, has been used for hundreds of years. Of course, it is very dangerous to eat. Some cultures that eat primarily cycad products show chronic problems related to cycad toxicity.

To avoid this problem, many cultures have developed ways to remove the toxins from the starch. These methods usually involve intense heating to denature the toxins, washing the starch thoroughly, or extracting the toxic parts directly (Often all three). The starch is often eaten directly, crushed into powder for seasoning and baking, or kneaded into dough and used to bake. For many early Japanese tribes and cultures, the king sago palm was a major factor in survival, particularly when normal food supplies were scarce. In more modern times it has been used as a carbohydrate source following natural disasters that destroy crops and livestock such as typhoons. Many local populations also used it during the 1940s during World War II to sustain themselves.

In addition to food, many cycads are used for alcoholic beverages. The king sago palm in particular is used to make a type of sake in Japan. The seed kernels are allowed to ferment for several days in order to prepare the drink. Unlike the food starch that is carefully cleaned and purged of toxins, the drink is prepared with some toxins still in the seed kernels. This makes drinking it exceedingly dangerous, and there have been multiple occasions where people have died drinking particularly strong batches. Of course, all alcoholic beverages are technically toxic, but this sake may be exceptionally so.