What is a good diet and workout plan to lose weight this summer?

Interval training: The best exercise you can do is a combination of cardio and strength training, called interval training. Using cardio and light weights you gain muscle. I use the nike training club app on my phone. There are likely interval classes at your local gym. If you calculate your calorie needs based on age/weight/height, you can determine # of calories to lose. My fitness pal is another great app.