What diet is recommended for acute gastroenteritis with loose watery stools?

Dietary Management for Acute Gastroenteritis with Loose Watery Stools

Continue a regular diet immediately without any dietary restrictions, focusing on starches, cereals, yogurt, fruits, and vegetables while avoiding high-sugar and high-fat foods. 1

Age-Specific Feeding Recommendations

Infants (Breastfed)

• Continue breastfeeding on demand without interruption throughout the entire diarrheal episode, as breast milk reduces stool output compared to oral rehydration solution alone 1, 2
• Never stop breastfeeding during rehydration or at any point during illness 1

Infants (Formula-Fed)

• Resume full-strength, lactose-free or lactose-reduced formula immediately after rehydration 1, 2
• Full-strength lactose-free formula reduces both stool output and duration of diarrhea by approximately 50% compared to gradual reintroduction 2
• If lactose-free formulas are unavailable, use full-strength lactose-containing formula under supervision, as many infants tolerate this well despite theoretical concerns about lactase deficiency 1
• Do not dilute formula, as this worsens nutritional outcomes and prolongs diarrhea 2, 3

Older Children and Adults

• Continue the regular diet immediately with foods including: 1
  • Starches: rice, potatoes, noodles, crackers, bananas
  • Cereals: rice, wheat, and oat cereals
  • Soup, yogurt, vegetables, and fresh fruits
  • Cereal-milk and cereal-legume combinations

Foods to Strictly Avoid

Eliminate foods high in simple sugars, as these exacerbate diarrhea through osmotic effects: 1

• Soft drinks and colas
• Undiluted apple juice
• Jell-O
• Presweetened cereals

Avoid high-fat foods, as they delay gastric emptying and may not be tolerated 1

The BRAT Diet: Use With Caution

The BRAT diet (bananas, rice, applesauce, toast) is reasonable for short-term use as it includes appropriate starches and fruits 1

Critical caveat: Prolonged use of the BRAT diet results in inadequate energy and protein content, which worsens recovery 1

Fluid Replacement Alongside Diet

While continuing regular diet, replace ongoing losses with oral rehydration solution: 1

• 10 mL/kg ORS for each watery or loose stool
• 2 mL/kg ORS for each episode of vomiting

Common Pitfalls to Avoid

Do not implement "bowel rest" or withhold food, as there is no justification for stopping feeding during diarrhea 3

Do not gradually reintroduce foods or use diluted formulas, as this approach delays nutritional recovery and prolongs illness duration 1, 2, 3

Do not diagnose lactose intolerance based solely on stool pH or reducing substances without clinical symptoms of worsening diarrhea 1, 2

When to Modify the Diet

Only consider temporary lactose reduction if true lactose intolerance develops, defined as more severe diarrhea specifically upon introduction of lactose-containing foods 1

The presence of low stool pH (<6.0) or reducing substances (>0.5%) without clinical symptoms does not indicate lactose intolerance 1

Nutritional Outcomes

Early reintroduction of full-strength feeding improves: 1

• Nitrogen balance
• Energy absorption
• Weight gain
• Arm circumference and skinfold thickness

These nutritional benefits occur while simultaneously reducing stool output 1