There is good news and bad news about the modern American food supply, and they are the same news: there is a dizzying variety of choices. This is true of the food supply in general, and of just about every category within it, from yogurt to chips and beverages to snack bars. A half-century ago, the typical supermarket offered about 15,000 choices; it now offers some 50,000.

This is bad news because a lot of these additions are highly-processed, and nutritionally rather dubious. But it’s good news as well, because some are just the opposite: minimally processed and quite wholesome.

It’s important to know how to find the latter, especially in the snack bar category, which many of us count on multiple times a day given packed schedules and an increasing need for on-the-go food. The snack bar aisle, from its origins as “granola” bars and, later, “cereal” bars, has evolved over the years to offer everything from energy for a workout to a meal replacement. Nutrition in this category really matters, because these bars can make up a significant part of our dietary routines.

The basic rules of good nutrition here are simple and generalizable to other food categories. In fact, they are the same five rules (or clues) we have long taught to kids (and their parents) in our Nutrition Detectives program. In this case, the sleuthing can be applied preferentially to snack bars.

First, get the information you need from the nutrition facts panel and ingredient list; the front of every package is about advertising, not education. Of course, once you know and trust a brand, you can trust the front of their package, too.

Second, remember that ingredients are listed in order of abundance; the product is mostly made from what comes first. In the case of a snack bar, that should be a wholesome food: a nut, a fruit, a whole grain. If sugar — under any alias — is the first ingredient, step away from the package, and nobody will get hurt! That’s a candy bar.

Third, avoid both identifiable, and unidentifiable junk, in the ingredient list. Identifiable junk would be items like partially hydrogenated oil or high-fructose corn syrup. Unidentifiable junk would be any long, complicated names (other than the names of vitamins) that refer to ingredients you can’t identify as food!

Fourth, remember that, in general, the shorter the ingredient list the better. The most wholesome foods come direct from nature and have an ingredient list just one word long, such as: almonds. The best packaged foods put wholesome ingredients together in tasty, convenient combinations, and add as little as possible to them to arrive at their recipe.

Fifth, make sure grains are “whole” grains, and look for fiber as proof of that. Fiber is beneficial in many ways. Among them, it helps to confer a lasting feeling of fullness at no cost in calories.

For snack bars specifically, however, we can go beyond these five clues and add one more: a generous dose of protein, because many of us look to snack bars to fill us up. Protein is the most satiating of the nutrient classes, meaning it is the best at making us feel, and stay, full. This is helpful for weight control, among other things. Second, protein is vital to working muscles; if snack bars help you fuel up for or recover from a workout, protein is key.

However, too much of a good thing is not good. Virtually no Americans are deficient in protein. Adults need, on average, only about 50 grams daily (one chicken breast provides more than half of this total) so snack bars that use protein concentrates to dole out 20 or 30 grams per bar are over-the-top, in my opinion. Despite the marketing hype, there is no established performance benefit of highly concentrated protein from isolates. Moreover, excessive protein on a daily basis can actually cause health problems over time, affecting everything from the liver and kidneys to the skeleton. I prefer to get my protein in reasonable doses from wholesome food sources I know are good for my overall health, than from protein isolates that have never been shown to confer any long-term health benefits.

My advice, then, is to focus on ingredients first. Look for nuts, seeds, fruits, and whole grains to predominate. Nuts and seeds are both rather good protein sources, and whole grains are moderate sources. Importantly, though, these foods are associated with good health outcomes over a lifetime, and are rich in a variety of beneficial nutrients, spanning vitamins, minerals, antioxidants, healthy oils, and fiber in addition to protein. Fruits add many more nutrients, although not much protein, and of course enhance taste.

While studies suggest that concentrated protein is satiating, the same is true of nuts, the routine consumption of which has been associated with numerous health benefits, including a reduced mortality risk overall. Along with protein, nuts provide fiber and mostly unsaturated fats. The combination appears to be more satiating than protein alone, and is decisively better for health. Fruits bump up the fiber content, and contribute to satiety as well. On the nutrition facts panel, look for a minimum of 2 grams of fiber, and 3 or more grams of protein. In general, get the ingredients right, and the nutrients, protein included, will take care of themselves.

The best snack bars are good because of what they do contain (healthful ingredients in a sensible, tasty combination, and protein from wholesome sources), and also because of what they don’t (sugar alcohols, artificial sweeteners). I keep these dos and don’ts in mind as I navigate the snack bar aisle, and recommend you do too.

David L. Katz, MD, MPH, FACPM, FACP, Senior Nutrition Advisor KIND Snacks, is recognized globally for expertise in nutrition, weight management, and the prevention of chronic disease. He is the founding director of Yale University’s Yale-Griffin Prevention Research Center; President of the American College of Lifestyle Medicine; and Editor-in-Chief of the journal, Childhood Obesity.