A Crowded Claims Market
The notion that food can prevent, treat, or cure disease is powerful and ancient. Modern wellness culture has amplified this idea to the point where dietary claims often outstrip evidence — "anti-inflammatory" diets, "gut-healing" protocols, and "immune-boosting" foods are marketed with a confidence that peer-reviewed science does not support. The truth lies between nihilism and hype: specific dietary interventions have strong evidence for specific conditions, while broad claims require scepticism.
What Has Strong Evidence
The low-FODMAP diet is the most rigorously tested dietary intervention in gastroenterology. Systematic reviews and meta-analyses confirm that the low-FODMAP diet reduces global IBS symptoms in 50 to 80 percent of patients, with improvements in bloating, abdominal pain, and stool consistency. It works as a structured elimination-and-reintroduction protocol — not a permanent restriction.
Exclusive enteral nutrition (EEN) — a formula-based liquid diet replacing all food intake for 6 to 8 weeks — is first-line therapy for inducing remission in paediatric Crohn's disease, with efficacy comparable to corticosteroids and superior mucosal healing. This is one of the most dramatic examples of food as medicine in gastroenterology.
The Mediterranean dietary pattern — characterised by high intake of fruits, vegetables, legumes, whole grains, olive oil, fish, and moderate wine — is associated with reduced cardiovascular risk, lower cancer incidence, reduced all-cause mortality, and improved microbial diversity in large epidemiological studies and interventional trials.
The gluten-free diet is essential and effective for coeliac disease — a strict, lifelong therapeutic intervention.
What Has Emerging Evidence
The Crohn's Disease Exclusion Diet (CDED), combining partial enteral nutrition with a whole-food diet excluding specific processed foods, has shown efficacy in paediatric and adult Crohn's disease in recent RCTs. Anti-inflammatory diet patterns (increased omega-3 fatty acids, polyphenol-rich foods, fibre diversity) show metabolic and microbiome benefits in observational and small interventional studies, but lack the large-scale RCT evidence of pharmaceutical interventions.
What Lacks Evidence
Detox diets, juice cleanses, alkaline diets, and most "gut-healing" supplement protocols lack clinical trial evidence. Claims that specific foods "boost immunity" misrepresent how the immune system works — you want a well-regulated immune system, not a boosted one. Collagen supplements for "gut lining repair" have no RCT evidence demonstrating mucosal healing.
The Balanced View
Diet is a powerful modulator of health — through microbiome effects, metabolic signalling, and inflammatory pathways. But "food as medicine" works best as a complement to, not a replacement for, evidence-based medical care. The most evidence-supported approach is a diverse, minimally processed, plant-rich dietary pattern — not a collection of individual superfoods or a rigid elimination protocol.