Get some exercise. Take a 30 minute walk every day. Keep a record of what and when you eat and your feelings at the time. Find ways to avoid the situations in which you overeat. Reduce or avoid many uncomfortable symptoms by gradually getting off caffeine as you prepare to quit smoking.
Some people become more sensitive to caffeine while quitting smoking.
Use portion control. Put everything you plan to have for your meal on your plate. Don't leave serving dishes out to tempt you to have more than you need. When you're full, leave the table. If your weight is increasing, take a careful look at your food choices.