Your son or daughter is going off to college or, for some other reason, is leaving home and you have concerns about a lot of things; not least among them, "is he / she going to be eating healthfully?" As in other aspects of life, you can give lots of good advice and helpful hints; whether or not they're accepted, however, is another matter ... and out of your hands.
My own kids (two sons and four daughters) have all had my crash course in Proper Grocery Shopping And What To Do With The Stuff When You Get It Home: 101. This consists of a trip to the grocery store where first we just read labels and compare prices. Then we look at vegetables, prepared foods, and "short cut" items and we discuss the different types of meat and what they are good for.
One of the things I have taught them to look for in a list of ingredients is the presence of partially-hydrogenated oils. These oils are major culprits in coronary artery disease. This has been well researched ... and yet, food manufacturers are still allowed to use them. These oils are found in cereals, crackers and cookies, and some prepared foods. They are the main ingredient in most margarines! If partially-hydrogenated oils are in the list of ingredients, don't buy the product. If your kids retain nothing else of what you tell them about nutrition, this one rule will guarantee them better health.
During our "field trip" I also tell them that the butcher and the greengrocer are there to help them make choices and to give advice, such as how to choose the best and freshest vegetables and fruits and how a particular cut of meat should be cooked.
Also important, economically speaking, are the instructions about the importance of picking up sale items, using coupons, and buying house brands instead of national brands. There is one exception to this rule: never buy house brand mayonnaise.
After all this "basic training", I then armed them with two of my recipes for things to keep in the fridge for days when blood sugar is so low you couldn't possibly prepare a meal. These are my Multi-Veggie Soup and my Complete Meal Pasta Sauce.
Both these recipes keep well in the refrigerator for a week or more and also freeze very well. They are reliable crowd pleasers.