Over eating in social gathering

When I go for a meal at some friend’s house and we start with a drink, I cannot wait to eat the appetizers on the table, such as peanuts and chips, and puff pastry, and all the little things in the middle of the table. I cannot stop myself to keep serving myself. I know that it is bad, but it gives me pleasure at the moment, so I eat it, and then I forget about it so I do not even feel guilty about it, well, until I got on the scale and see the numbers up… How do I stop ??! PLEASE?!