This study is a randomized controlled trial with 120 overweight or obese (body-mass index, BMI, 24 kg/m) participants and 20 normal-weight participants. Twelve weeks of energy-restricted nutritional and lifestyle intervention with placebo, Lactobacillus paracasei LC-19 (LC-19), or semaglutide (a glucagon-like peptide-1 receptor agonist, GLP-1RA) will be randomly conducted in the overweight or obese participants. The primary goal is to clarify the roles of LC-19 and semaglutide in weight reduction and in improving energy, glucose, and lipid metabolism, while also comparing side effects, adverse events, and long-term outcomes such as weight regain between these two interventions. In addition, the study will explore key factors affecting intervention response to provide evidence for optimizing individualized intervention strategies.