This situation can be avoided with the magic of portion control!
Sure, all the food looks great. But this (most likely) will not be your last meal ever, so don't eat like you're never going to see food again! Think about what you want to have the most: is it more important to have the potato salad or the corn? Pick one, and only take a small amount of it. Just because something is healthy doesn't mean you should eat a ton of it! Did you know that eating too many seemingly-healthy walnuts can cause severe stomach aches? The most important thing to remember when navigating through the reckless meals of summer is that eating should not control your life. Don't stuff yourself with food you don't need just because it tastes delicious, but also don't become obsessed with your diet.
And most importantly:
My secret to staying healthy over the summer is only drinking water! I don't really like soda, so this isn't hard for me, but by cutting sugary drinks out of your diet, even if it's just for the season, you can prevent gaining a lot of weight!
So, what's your trick to staying slim all summer?