The effects of the dietary inclusion of two levels of short-chain fructooligosaccharides (sc-FOS) on weight loss, biochemical parameters and serum haptoglobin concentration were investigated in twelve experimental obese Beagle dogs. Dogs were randomised into two groups and submitted to a weight loss program (WLP): the control group (C) received a commercial energy-restricted high-protein diet containing 1 % DM sc-FOS, whereas the test group (T) received the same diet enriched with sc-FOS to attain a 3 % DM content. Body weight (BW) and body condition score were weekly assessed in each dog and blood was collected before and after WLP to measure total plasma cholesterol (CHOL), TAG, NEFA, glucose (GLUC), insulin, serum leptin and haptoglobin. Groups showed similar BW and blood parameters before treatment. When values before and after treatment of the dogs were compared, significant reductions were observed for all parameters, with the exception of NEFA and GLUC. However, when these reductions were compared between C and T groups, significant differences were detected only for haptoglobin (T before v. T after: 1545 v. 605 mg/l, P = 0·03; C before v. C after: 1635 v. 1400 mg/l, P = NS). Positive correlations between haptoglobin and CHOL and between haptoglobin and TAG were observed before but not after WLP. In conclusion, feeding obese dogs with the energy-restricted diet caused significant weight loss and reduction of blood parameters, irrespective of the sc-FOS content included. However, serum haptoglobin level, and the subclinical inflammatory condition associated with it, was significantly lowered in the T but not in the C group.