What You Need to Know About Carbs

Updated July 2026

Few nutrients are as misunderstood as carbohydrates. Depending on which headline you read last, carbs are either making you fat, wrecking your cholesterol, or the foundation of the world's longest-lived diets. The truth is that "carbs" is far too broad a category to be good or bad, and once you understand the real dividing line, most of the confusion falls away. Here's what actually matters.

Are carbs bad for you?

No, and this is where most of the confusion starts. "Carbohydrate" is an enormous category that includes both a glazed donut and a bowl of black beans, foods that do almost opposite things in your body. Lumping them together and asking whether "carbs" are bad is like asking whether "liquids" are bad, when the answer depends entirely on whether you mean water or gasoline. The problem was never carbohydrates as a class. It's that a handful of heavily processed carbs have given the whole group a bad name.

Why do nutrition labels mislead you about carbs?

Because a label counts grams without telling you what those grams actually do in your body. The nutrition panels for gummy bears and apples can look surprisingly similar, apples even come out looking "worse," with more carbs and sugar and less protein than the candy. Yet everyone knows an apple builds health and gummy bears don't. That gap between what the panel says and what the food does is the whole point: there is far more to nutrition than can be captured by a row of macronutrient numbers, and judging carbs by grams alone will lead you straight to the wrong conclusion.

What's the real difference between "good" and "bad" carbs?

How fast they turn into sugar in your bloodstream, and what that does to your insulin. Highly processed, simple carbohydrates, like soda, candy, white bread, and crackers, are digested quickly and flood your bloodstream with sugar. That spike triggers a surge of insulin, and insulin, among other things, ramps up the liver enzyme that manufactures LDL. The result is not just higher blood sugar, but also higher bad cholesterol.

Complex, unprocessed carbohydrates, like oats, flax, chia, beans, and most fruits and vegetables, behave completely differently. Their fiber slows digestion to a trickle, so sugar enters the bloodstream gradually, insulin stays low, and LDL stays down. Same macronutrient category on the label, opposite effect in your body. If you want the outside view, here's how the Harvard School of Public Health explains it.

How can you tell good carbs from bad without overthinking it?

Let nature be your guide. It has already created near-perfect carbohydrate foods, and they tend to come with fiber built in, well over 2 grams of fiber per 100 calories. That ratio gets you to about 40 grams a day on a 2,000-calorie diet, right in the bullseye for healthy eating, and roughly what whole-food vegans and vegetarians tend to eat. Step One Foods runs higher still, closer to 3 grams per 100 calories. Black beans, oats, blueberries, spinach: you can eat these in almost unlimited quantities without harm. What to limit are carbohydrates that have been heavily modified from their original form, like those gummy bears.

But don't fall for the lazy shortcut that "anything in a box is processed and therefore bad." Cooking from scratch is a form of processing, and so is slicing a tomato, yet neither meaningfully changes the nutritional value of your food. The better question isn't whether a food comes in a package, it's what's actually in it. A simple test: if your great-grandmother wouldn't recognize the ingredients on the label, skip it.

Doesn't Step One Foods have carbs and sugar on the label?

It does, and it's a perfect illustration of why the label alone misleads. The nutrition panel for our blueberry oatmeal shows 26 grams of carbs and 7 grams of sugar. But look at where those come from: whole oats, flax seeds, whole blueberries, cranberries, and Saskatoon berries, plus the bare minimum of apple juice concentrate needed to keep the dried berries soft enough to chew. Every one of those is a whole-food carbohydrate your great-grandmother would recognize. Same numbers on the panel as some junk foods, completely different effect on your body.

So how should you think about carbs?

Step away from the macronutrient math and the fad-diet noise. The diet most consistently linked to healthy longevity is not high-protein or high-fat, it's actually high in carbohydrates, the good kind: plenty of fruits, vegetables, whole grains, and legumes, with modest amounts of healthy plant-based fats. It's close to the opposite of what most trendy diets preach. The best dietary advice ever written still fits in seven words, from Michael Pollan: Eat food. Not too much. Mostly plants. Follow that, and your carbs, sugar, protein, and fat will all take care of themselves.

Read the rest of the "What You Need to Know" series: cholesterol and inflammation.