BACKGROUND Increased consumption of sweetened beverages has previously been linked to the degree of childhood obesity. OBJECTIVE The aim of the present study was to assess whether the intake of sweetened beverages, candy, snacks or fast food at baseline in a multidisciplinary childhood obesity treatment program was associated with the baseline degree of obesity or the treatment effect. METHODS This prospective study included 1349 overweight and obese children (body mass index standard deviation scores (BMI SDS) ≥ 1.64) enrolled in treatment at The Children's Obesity Clinic, Copenhagen University Hospital Holbaek. The children were evaluated at baseline and after up to 5.9 years of treatment (median 1.3 years). RESULTS Both boys and girls decreased their BMI SDS during treatment with a mean decrease in boys of 0.35 (p < 0.0001) and in girls of 0.22 (p < 0.0001) after 1 year of treatment. There were no associations between the baseline intake of sweetened beverages, candy, snacks, and/or fast food and BMI SDS at baseline or the change in BMI SDS during treatment. CONCLUSIONS The intake of sweetened beverages, candy, snacks or fast food when entering a childhood obesity treatment program was not associated with the degree of obesity at baseline or the degree of weight loss during treatment.