I have heard/read several times now about music, light, and/or scents in various mediums and combinations. The gist is that fast, loud music encourages a person to eat and/or drink more and to do it faster. Different lighting also affects how much/how fast we consume, too; brighter light seems to cause us to eat more/faster than dimmer light. Scents might be the most powerful of all, because when we smell good food, we want to eat it. The idea is to play quiet, soothing music, light (not food/spice scented) candles or dim the lights, and put flowers or potpourri on the table if you aren't using scented candles. This, plus putting food on plates in the kitchen and NOT having bowls of food (except maybe salad) on the table, encourages us to eat less and eat more slowly.

I thought this might help with eating with other people, and it may be a way to help you to stick to your plan.