Malabsorption: This is often the most common reason for sticky feces in adults, typically due to conditions like celiac disease, pancreatic insufficiency, or small intestine bacterial overgrowth (SIBO), which lead to the malabsorption of fats and other nutrients, resulting in sticky or greasy stools.

Gastroesophageal Reflux Disease (GERD): While more commonly associated with heartburn, some individuals with GERD may experience changes in stool consistency, including stickiness, possibly due to altered gut motility or the effects of chronic inflammation on the gastrointestinal tract.
Irritable Bowel Syndrome (IBS): IBS can cause a variety of bowel symptoms, including changes in stool consistency. Some patients may experience sticky feces, although this is less common than other symptoms like abdominal pain, bloating, or changes in bowel frequency.
Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can lead to inflammation of the gastrointestinal tract, potentially causing changes in stool, including stickiness, especially during active disease phases.

Cancer (e.g., Pancreatic Cancer): Although less common, pancreatic cancer can cause malabsorption leading to sticky stools due to the tumor's interference with pancreatic enzyme production. Early detection is crucial, making this a "do not miss" diagnosis.
Diabetic Enteropathy: Diabetes can cause neuropathy affecting the gut, leading to gastroparesis or other motility issues, which might result in changes in stool consistency, including stickiness.
Thyroid Disorders: Both hyperthyroidism and hypothyroidism can affect bowel movements. Hyperthyroidism is more commonly associated with diarrhea, but hypothyroidism can sometimes lead to changes in stool consistency.

Amyloidosis: A condition characterized by the deposition of amyloid proteins in various tissues, including the gastrointestinal tract, which can lead to malabsorption and changes in stool consistency.
Whipple's Disease: A rare, systemic bacterial infection caused by Tropheryma whipplei, which can lead to malabsorption, weight loss, and changes in stool, including diarrhea or sticky feces.
Short Bowel Syndrome: Typically resulting from significant surgical resection of the small intestine, this condition can lead to severe malabsorption, including the malabsorption of fats, which may cause sticky stools.