A review of the evidence by the National Institute for Health and Clinical Excellence (NICE) found obesity to be a significant but small risk factor for gasto-oesophageal reflux disease (GORD). There was insufficient evidence that other factors are a significant risk in the development of GORD, peptic ulcer disease, or non-ulcer dyspepsia.

• NICE found a lack of randomized controlled trials examining the effect of lifestyle on dyspepsia. A search of epidemiological evidence identified 28 cross-sectional or case control studies that evaluated the association between dyspepsia and obesity, smoking, alcohol, coffee, chocolate, or fatty food intake.
• Obesity: six trials compared subjects with reflux symptoms with the general population. Four studies found a positive association of obesity and GORD, and two found a negative association. NICE concluded that, overall, there did appear to be a a positive association between obesity and GORD, although in most studies the odds ratios were less than two, indicating a modest effect.
• Smoking: seven studies evaluated smoking status with either oesophagitis or reflux symptoms. Three reported a statistically significant positive association, three no association, and one a negative association. Most studies reported odds ratios of less than two indicating that any association that exists is likely to be small. Overall, NICE concluded that smoking does not have a significant causal relationship with GORD.
• Alcohol: seven studies examined the relationship between alcohol intake and oesophagitis and reflux symptoms. Four reported no statistically significant association, and three a positive association. Odds ratios were all less than two. Overall, NICE concluded that there was no significant association between alcohol and GORD.
• Coffee: eight studies assessed coffee intake and upper gastrointestinal symptoms. Six found no statistically significant association and two reported a negative association.
• Chocolate: one study found no statistically significant association between chocolate intake and dyspepsia symptoms. NICE concluded that there is insufficient evidence that chocolate has a role in the aetiology of GORD.
• Fat intake: two studies assessed the association between fat intake and reflux symptoms in more than 20,000 subjects. No statistically significant association was found between fat intake and symptoms.