What is gastroparesis?

Gastroparesis is a chronic gastrointestinal motility disorder where the stomach empties food more slowly than normal, in the absence of a physical blockage. Under normal conditions, coordinated contractions of the stomach muscles — regulated by the enteric nervous system — grind and propel food into the small intestine for further digestion. This process typically occurs over 2-4 hours after eating.

In gastroparesis, this coordination is disrupted. As a result, food can remain in the stomach for too long, leading to symptoms such as:

• Nausea
• Early satiety (feeling full quickly)
• Abdominal pain or bloating
• Vomiting (often of undigested food)

People with gastroparesis sometimes struggle to meet their energy and micronutrient needs, which may result in weight loss or nutritional deficiencies. As such, dietetic input is essential to support adequate nutritional intake and symptom management.

What causes gastroparesis?

Gastroparesis has several potential causes, although in many cases, the underlying mechanism remains unclear:

• Diabetes mellitus: One of the most common known causes, usually related to high blood sugars
• Idiopathic: No identifiable cause is found.
• Post-surgical: Particularly after upper gastrointestinal or vagus nerve-involving surgeries
• Medication-induced: Certain medications including opioids and GLP-1 receptor agonists can delay gastric emptying.
• Connective tissue disorders:  Such as systemic sclerosis, which can impair smooth muscle function.
• Eating disorders: Chronic undernutrition and altered gut-brain signalling can contribute to motility dysfunction.

How is gastroparesis diagnosed?

Usually, other conditions will need to be ruled out before diagnosing gastroparesis. A gastroscopy (also known as an OGD) can be performed by inserting a camera attached to a thin tube into the stomach via the mouth. If this test is normal and no other causes are suspected for the symptoms, gastric emptying scintigraphy may be carried out. This is done in a nuclear medicine department, and requires the person with suspected gastroparesis to eat a meal containing a radioactive substance, so the progress of the meal through the stomach can be visualised on an external camera. If the food empties from the stomach at a slower rate than standardised reference values, then gastroparesis is diagnosed. Alternative diagnostic tools include 13C breath testing, although these are less commonly used in routine practice⁽¹⁾.

How is gastroparesis managed?

Gastroparesis management often involves a combination of strategies tailored to the individual. While medications such as antiemetics or prokinetics may help some people, and more invasive treatments such as botulinum toxin (botox) and gastric pacemakers are available in selected cases, these options are not suitable for everyone and may have limited supporting evidence.

In contrast, dietary modification is a central and accessible part of symptom management, even though research in this area is still emerging. The most widely recommended strategy is a “small particle size” diet, based on two Swedish studies in individuals with diabetic gastroparesis^{(2, 3)}. This involves foods that can be easily mashed with a fork (e.g., soft potatoes) and excludes:

• Foods with husks, skins, or membranes
• High-fibre or stringy vegetables
• Whole grains, rice, pasta
• Dense meats and cheeses
• Fresh white bread

Low-fat and low-fibre diets have also been proposed, but again, the research behind them is limited and inconclusive.

Because gastroparesis can severely affect dietary intake, nutritional status, and quality of life, referral to a specialist dietitian is strongly recommended. Dietitians can provide personalised strategies to optimise food tolerance while ensuring adequate energy and nutrient intake.