Study aim: effects of Slimtak (Combination of green tea dry extract and Cichorium intybus roots Extract) compared to placebo on weight loss in obese or overweight adults Design: Clinical trial with placebo control group, with parallel groups, double blinded, randomized, on 80 individuals with overweight/obesity, randomization with blocks of size 4 using software Settings and conduct: The place of the study: private clinic in Tehran; Population: people with overweight and obesity; type of blinding: double blinded; blinding, randomization and preparation of supplement cans will be done by a trained person outside the study until participants, researchers and analyzer remain blind until the end of the analysis. At the beginning and end of the intervention with supplement or placebo weight, height, BMI, and body composition will be measured. Participants in both groups will receive weight loss diets based intervention with supplement/placebo during the study period. Study duration will be 8 weeks. Participants/Inclusion and exclusion criteria: Inclusion criteria: BMI:25-40, age: 18-65 years, and willing to participate in the study. Exclusion criteria: Using weight reduction medication, substance overuse, pregnancy or lactation, having known kidney disease, and having known heart disease Intervention groups: Supplement group: 3 Slimtak capsule with each meal and weight reduction diet, Placebo group: 2 placebo capsules with each meal and weight reduction diet for 8 weeks Main outcome variables: weight; fat mass; fat free mass; BMI