Portion control may be the main thing that is your struggle. If so, drinking hot herbal tea right after you wish to be done eating can help you stop. Don't try to prepare it after u eat. Have it ready prior to either eating or prior to u finishing.
Some teas to consider- peppermint, chamomile, dandelion leaf, nettles, ginger, burdock, tea labeled as helping digestion or stomach, passionflower, skullcap, gentian.