Phosphorus inhibits the absorption of calcium, and many of the items we feed our gliders have high phosphorus to calcium ratios. Because of this it is very important to supplement calcium in their diets, being sure to use a calcium supplement that doesn't contain phosphorus. Fats and Sweets Gliders have a real sweet tooth, and can be little pigs when it comes to sweets and fatty foods. My first pair of gliders were not tame, so when I discovered foods they particularly liked, I'd use them as bribes to get them to trust me. Pecans were a favorite, as were sugar cubes.
Many pet stores make the mistake of advising their customers to feed gliders parrot seed mixes.
If having a plump glider doesn't bother you, there are other things to consider. Fatty deposits can build up in the eyes, causing blindness. And gliders fed an improper diet can develop very strong smelling urine. They've been around gliders whose diets were not correct. Just plain overfeeding The third case I've only seen once.