How many carbs should you eat in a day?

Want to know how many carbs per day you should be eating? First, a hearty round of applause from everyone at WeightWatchers for knowing that carbs should be part of your diet at all. We’ve always stood on science that bread belongs at the table, despite the carbless (joyless) sentiment that’s trended for a couple decades at this point. But back to brass tacks: Your carbohydrate intake should be personalized to you — and we can help. Here’s your comprehensive guide to figuring it all out, plus the nitty gritty on all the different kinds of carbohydrates out there.

What are carbohydrates?

Carbohydrates are, at their core, a key source of energy for the body. “Carbohydrates can be converted to glucose, the body's main source of energy,” says Jennifer Maeng, R.D., a registered dietitian and founder of Chelsea Nutrition in New York City. So, they keep your muscles, brains, and cells going. Compared to the other two macronutrients — protein and fat — your body can digest carbs much more quickly, meaning they give you energy faster. Carbs can be grouped into two buckets: simple carbohydrates and complex carbohydrates.

Simple carbohydrates

Simple carbohydrates are basically sugars with just one or two molecules and require very little digestion to be turned into glucose. Since they’re so easy to process, simple carbs can give you a quick burst of energy. But that has a flip side. As that quick blood sugar spike goes away, your blood sugar can drop quickly, says Maeng. This can leave you feeling hungry sooner and also tired or cranky. Fruit juice and table sugar are two examples of simple carbs.

Complex carbohydrates

Complex carbohydrates, which include fiber and starches, consist of long chains of sugars and therefore take longer to digest (or in some cases, don’t get digested at all). This allows for a slower release of glucose, which helps you feel fuller for a longer stretch of time, according to Maeng. And because of that, they generally don't cause a blood sugar crash the same way simple sugars do. Whole grains and vegetables are both sources of complex carbs.

Types of carbs

Another way nutrition experts sometimes classify carbs? Sugars (which are simple carbs), starches (which are complex carbs), and fibers (which are also complex carbs). Here’s a quick primer:

Sugars

Sugars (aka simple carbs) include added sugar, like what you’d find in a can of soda, as well as the sugar from natural sources like honey or agave. As the quickest carbs for your body to digest, sugars are readily transported to the bloodstream, giving you a quick hit of energy, according to Maeng.

Starches

Starches are complex carbohydrates found in potatoes, grains, and corn. These “break down more slowly than sugars,” says Maeng. Like sugars, though, they are turned into glucose, which is then picked up by the bloodstream to fuel functions throughout the rest of your body.

Fibers

Fiber is another complex carbohydrate, but it behaves differently than starch. Fiber “aids digestion and is metabolized by the gut microbiome,” says Maeng. “It works as a ‘fertilizer’ for the good bacteria in your gut.” Found in vegetables, fruits, nuts, and beans, fiber is considered indigestible. “Sugar and starch are broken down by the body into glucose, whereas the body cannot break fiber down,” says Keri Gans, RDN, a registered dietitian in New York, NY. Because it sticks around in the digestive tract, it helps boost satiety (or feelings of fullness) and may also help reduce cholesterol.

There are two different types of fiber: Soluble fiber, found in oatmeal and beans, can dissolve in water. In your digestive tract, it creates a gel-like material that slows digestion and can lower blood sugar. Insoluble fiber doesn't dissolve and just passes through your digestive tract as it is, helping keep bowel movements regular. This includes your whole grains, nuts, and fruit skins.

How many carbs do you need in a day?

According to the latest Dietary Guidelines for Americans, carbohydrates should account for 45% to 65% of your total calorie intake. That goes for both men and women (anyone over the age of two). Each gram of carbohydrates has four calories, so that works out to 225 to 325 grams of carbs a day if you’re eating a 2000-calorie diet.

How to calculate your carb needs

You can use the dietary guidelines as a good range for your individual carbohydrate requirements, but it is a big range. To help you see where you should land, factor in your own preferences and goals. “For example, active individuals often require more convenient sources of energy,” says Maeng. Think bananas or apples, or those sports energy gels that long-distance runners use; these are rich in simple sugars. Meanwhile, people who are less active may need fewer carbs to help them maintain their weight.

Any time you adjust your daily calorie intake, you also need to recalculate your carb intake. If you’re eating fewer calories overall, that reduces how many carbs you eat in a day. To help figure out your needs (and answer any other nutrition-related questions), all WeightWatchers members have access to personalized advice from a registered dietitian. Another tool for members: You can now check My Day in the app to see all of your macro intake, including carbohydrates, and make sure you’re on track.‍

Benefits of eating low carb

One approach (but not the only one!) to weight loss is a low-carb diet, which the National Institute of Medicine defines as eating between 25 grams and 150 grams of carbs each day. The exact amount depends on your calorie intake and the diet plan you’re following. Before reducing your carbs, know that you may inadvertently reduce the amount of fiber you eat and miss out on the health benefits of eating complex carbs. You may also find it tough to stick with over time, says Maeng. But if you do decide to go low-carb, here are some of the ways it can impact your health:

Weight loss

If you’re thinking of reducing your carb intake as part of a weight-loss program, there’s evidence that it can help. A 2023 review of the existing literature found that people lost the most weight when they decreased their carb intake to 5% of their total calories over the course of 12 months. But when they looked at more long-term weight loss, the highest reduction in weight came when people ate 30% of their calories from carbs. This may be due to how unsustainable it is to eat just 5% of your calories from carbs.

What’s worth keeping in mind is that certain carbs — specifically fiber and low-carb vegetables — can actually help with weight management. A 2023 paper determined that swapping refined grains like white bread (a source of sugars) and starches for fiber-rich whole grains helped minimize weight gain over the course of 24 years.

Other benefits

Eating less carbs may also improve your heart health. A study in the Annals of Internal Medicine found that a low-carb diet — which was rich in low-carb vegetables but otherwise didn't restrict fat or protein — led to an 11% reduction in body weight after one year. But on top of that, the people on the low-carb diet also reduced their blood pressure, lowered their LDL (bad) cholesterol, and increased their HDL (good) cholesterol after just six months. Part of the reason for this is that “adopting a low-carbohydrate diet may help stabilize blood sugar, which protects individuals against diabetes and insulin resistance,” says Maeng.

Do carbs make you gain weight?

Carbs don’t necessarily make you gain weight, but taking in too many calories can. “Almost any food eaten in excess within one’s diet has the potential to cause weight gain,” says Gans. And simple carbs can be especially easy to overeat, since they’re less likely to make you feel full (as they’re so easily digested) and have been shown to activate the brain’s reward systems — both of which make you want to eat more.

The bottom line

Carbohydrates can fall into one of two categories: Simple carbs, or sugars, which are digested quickly and send your blood sugar up rapidly then back down just as fast, and complex carbs, which are digested more slowly and give you sustained energy. Complex carbs can be either starches or fibers. It’s recommended that most people get between 45% and 65% of their total calories from carbs, but your exact needs depend on things like activity level and if you’re trying to lose weight or not. Research does show that eating a low-carb diet may be able to help you lose weight, but you could lose out on the health benefits of eating complex carbs and this approach could be unsustainable, especially if you go too low.