For years I have done this 3-day diet analysis project where students write down what they eat for 3 days without changing what they normally do, and then add up their calories, fat grams, protein grams, etc. and see whether they have a healthy diet. Students are often really surprised about the fact that they do not have healthy diets! Each student will need 3 diet log pages, one for each day and the instructions page. You can give them a 4th log page to be done after the analysis of their 3-day diet when they are able to come up with a sample "good day" diet plan.