This study examined the effects of a long-term Palatinose (Pala)-containing diet, with or without exercise, on blood pressure (BP), body weight (BW), the progression of diabetic nephropathy (DN), and metabolic syndrome (MetS) component factors including visceral fat mass (VFM), glucose intolerance, and dyslipidemia in an obese diabetic rat model. Twenty-eight male Otsuka Long Evans Tokushima Fatty (OLETF) rats aged 24 weeks were assigned to the sedentary (OLETF-Sed), Pala-containing diet (OLETFPala), exercise (OLETF-Ex), and combination of Pala with exercise (OLETF-Pala & Ex) groups. The OLETF-Ex and OLETFPala & Ex groups were allowed to run voluntarily on a rotatory wheel. BW and BP were measured weekly from 24 to 29 weeks of age. Pre and posttreatment serum glucose, insulin, and leptin concentrations, as well as body composition were measured, and 24 h urine samples were collected for measurements of protein excretion. After treatment, measurement of serum lipid levels and kidney morphological analysis were performed. The OLETF-Sed group showed increased BW and VFM, decreased lean body mass (LBM%), and deterioration in MetS component factors. The OLETF-Ex group showed decreased VFM and increased LBM%, and improvement in all MetS component factors posttreatment. However, both groups showed increases in BP and progression of DN after treatment. The OLETF-Pala and OLETFPala and Ex groups improved in all MetS component factors measured and did not show BP increases or progression of DN. This study demonstrated that a Pala-containing diet alone or combined with exercise improved MetS component factors without progression of DN.