a Mean(s.d.) bodyweight of mice after 6 weeks on a standard (SD) or Western (WD) diet. Abx, after antibiotics; POD, postoperative day. *P < 0.050, †P < 0.010 (unpaired 2-tailed t test, 5 mice per group). b Longitudinal analysis of stool mass. F (1,8) = 33.87, P < 0.001 between groups (2-way ANOVA; 30 per group at the start of the experiment, decreasing to 3 per group at the end as mice were killed every 3 days). *P < 0.050 versus WD (Student’s t test). c Longitudinal analysis of anastomotic healing score (AHS), showing area under the curve for AHS. F (1,28) = 18.78, P < 0.001 between groups (2-way ANOVA). d Mean(s.d.) AHS and individual values. *P < 0.001 versus SD (t test). e Mean(s.d.) AHS on POD 5 in separate groups of WD and SD mice exposed to antibiotics and colorectal surgery. Shaded area indicates anastomotic leak. *P = 0.021 versus SD (t test). Four of five WD-fed mice had an AHS of 3 (abscess) or 4 (peritonitis), whereas only one of five of SD-fed mice had an AHS of 3 (abscess).