Cholecystokinin (CCK) is a peptide family that functions pancreatic enzyme secretion, gallbladder contraction, intestinal motility, satiety, and stomach acid secretion. The CCK peptides are derived from pro-CCK with a specific amino acid sequence (Asp, Tyr, Met, Gly, Trp, Met, Asp, and Phe) at their C-terminus, where the Tyr residue is sulfated. The CCK peptides are ligands of the CCK receptors 1 (CCK1) and 2 (CCK2). In this study, we propose an approach for treating overweight and obese patients, preventing or reducing CCK1 activation using compounds that specifically interact with CCK peptides to regulate their interactions with CCK1. The compounds were selected by molecular docking using a chemical library with the selected residues (Asp, Tyr, Met, Gly, Trp, Met, Asp, and Phe) in CCK. Their effects were evaluated in a diet-induced obese mice model. We show that compounds K2 and K5 decreased and maintained the body weight of the diet-induced obese mice model, respectively, likely by preventing/hindering interactions between CCK peptides and CCK1, modifying its activity. This study demonstrates another approach to treating overweight and obesity by regulating CCK1 functions. The K2 and K5 compounds have properties supporting their continued development as new drugs against these risk factors.