In a perfect world, we would all be living on farms and eating directly from the fields and off the trees. In the real world: we have the supermarket. Navigating shelves of processed food for familiar ingredients can often seem like a daunting task, but food labels are unfortunately an often-ignored crucial window into our daily nutrition—which extends far beyond a “whole grain” or “organic” marker. Understanding them plays an important role in shaping how we make informed decisions to fuel our bodies.

The key mistake many make is assuming that the front of a package’s claim holds all the answers. Not true! When manufacturers take out some ingredients to make a food lower-fat or lower-calorie, they have to replace those compounds with something else to make sure the final product is both recognizable and stable.

Sugar-free foods, for example, are usually things like cookies or cakes—in other words, “sweets.” To get that same taste, there has to be a catch. In this case, the catch will almost always be a chemically derived additive. In the same way that you should then be looking for identifiable ingredients like stevia or maple as the most healthful replacements for sugars, you should also be aware of the most wholesome replacements for other additives whose function you may be less familiar with.

As many consumers lose trust in big food production corporations, many companies are trying to keep up with demand by removing what some might see as extraneous additives. At the end of the day, though, what really matters isn’t what’s being taken out—it’s what’s being left behind.

Let’s start with the basics.

Flip over the box of any number of “simple” foods in your pantry, and you might be surprised at the complexity of what you see. At least the ingredients list should always start out strong. In the United States, ingredients of a product are listed in order of greatest to least weight at the time they are added to the product. While some modifiers you see tacked on to familiar components might sound complicated at first glance, many just refer to simple processes like dehydration (“reverse-osmosis whey protein”) or cold-pressing (“expeller-extracted grape seed oil”).

But just like that tub of ice cream you’re looking at, the ingredients list gets stickier the farther down you go.

For multi-ingredient components that make up less than 5% of the overall food, manufacturers might choose to list the element itself and not its constituent parts—like referring to the “tomato sauce” on a pizza instead of the concoction of tomatoes, herbs and spices. This rule does not apply when an additive within one of those parts serves a function, like as a stabilizer or thickening agent. This is good news for people with allergies or sensitivities to some of the nastier additives that they might not otherwise suspect would be lurking.

Carrageenan is an example of one natural additive that can replace many synthetic or animal-based gumming agents that can act the same way but require the use of multiple chemicals to do so. This keeps food labels shorter, more straightforward and easier to read. For those looking to make the healthiest choice, it is always best to side with science.

With that said, the same caution toward dangerous traces also applies in the other direction: food science is not exact, and it’s important to remember that no label can dictate your health. If you’re especially stressed out or sick, for example, you might need more vitamin C than the calculated total based on a 2,000-calorie diet, and a serving size might not apply. As always, the best defense is a good offense. In this case, that’s being an informed consumer. Learn more about what each section of the nutrition facts label means—and what changes have been proposed—and shop smarter.