Low carbohydrate diets can be very effective for weight loss, according to research.
Reducing carbs tends to reduce your appetite and cause automatic weight loss, or weight loss without the need to count calories.
For some people, a low carb diet allows them to eat until fullness, feel satisfied, and still lose weight.
The number of carbs a person should eat every day for weight loss varies depending on their age, sex, body type, and activity levels.
This article reviews how many carbs you should eat per day to lose weight.
The Dietary Guidelines for Americans recommends that carbs provide 45–65% of your daily calorie intake for all age groups and sexes (
According to the Food and Drug Administration (FDA), the Daily Value (DV) for carbs is 300 grams per day when eating a 2,000-calorie diet (2).
Some people reduce their daily carb intake with the aim of losing weight, cutting down to around 50–150 grams per day.
Research has shown that low carb diets can be part of an effective weight loss strategy.
This diet restricts your intake of carbohydrates — including sugars and starches like bread and pasta — and replaces them with protein, healthy fats, and vegetables.
Studies show that low carb diets can reduce a person’s appetite, lead to them eating fewer calories, and help them to lose weight more easily than in other diets, provided they maintain the diet (
In studies comparing low carb and low fat diets, researchers need to actively restrict calories in the low fat groups to make the results comparable, but the low carb groups are still usually more effective (4,
Low carb diets also have benefits that go beyond just weight loss. They can help to lower blood sugar, blood pressure, and triglycerides. They can also help to raise HDL (good) cholesterol and improve the pattern of LDL (bad) cholesterol (
Low carb diets often cause more weight loss and improve health when compared to calorie-restricted, low fat diets that many people still recommend. There’s plenty of evidence to support this idea (8, 9,
Summary Many studies show that low carb diets can be more effective and healthier than low fat diets.
There’s no clear definition of exactly what constitutes a low carb diet, and what’s low for one person may not be low for the next.
An individual's optimal carb intake depends on their age, gender, body composition, activity levels, personal preference, food culture, and current metabolic health.
People who are physically active and have more muscle mass can tolerate a lot more carbs than people who are sedentary. This particularly applies to those who do a lot of high intensity exercise, like lifting weights or sprinting.
Metabolic health is also a very important factor. When people develop metabolic syndrome, obesity, or type 2 diabetes, their carb needs change.
People who fall into these categories are less able to tolerate a lot of of carbs.
Summary The optimal carb intake varies between individuals, depending on activity levels, current metabolic health, and many other factors.
If you simply remove the unhealthiest carb sources from your diet, such as refined wheat and added sugars, you'll be well on your way to improved health.
However, to unlock the potential metabolic benefits of low carb diets, you also need to restrict other carb sources.
There are no scientific papers that explain exactly how to match carbohydrate intake to individual needs. The following sections discuss what some dietitians believe about carb intake and weight loss.
Eating 100–150 grams per day
This is a moderate carb intake. It may work for people who are lean, active, and trying to stay healthy and maintain their weight.
It’s possible to lose weight at this — and any — carb intake, but you may also need to be aware of calorie intake and portion sizes to lose weight.
Carbs you can eat include:
- all vegetables
- several pieces of fruit per day
- moderate amounts of healthy starches, like potatoes, sweet potatoes, and healthier grains, like rice and oats
Eating 50–100 grams per day
This range may be beneficial if you want to lose weight while keeping some carb sources in the diet. It may also help to maintain your weight if you’re sensitive to carbs.
Carbs you can eat include:
- plenty of vegetables
- 2–3 pieces of fruit per day
- minimal amounts of starchy carbs
Eating 20–50 grams per day
This is where the low carb diet has bigger effects on metabolism. This is a possible range for people who want to lose weight fast, or have metabolic problems, obesity, or diabetes.
When eating less than 50 grams per day, the body will go into ketosis, supplying energy for the brain via so-called ketone bodies. This is likely to dampen your appetite and cause you to lose weight automatically.
Carbs you can eat include:
- plenty of low carb vegetables
- some berries, maybe with whipped cream
- trace carbs from other foods, like avocados, nuts, and seeds
Be aware that a low carb diet doesn’t mean it’s a no-carb diet. There’s room for plenty of low carb vegetables.
It’s important to experiment
Each individual is unique and what works for one person may not work for the next. It’s important to do some self-experimentation and figure out what works best for you.
If you have type 2 diabetes, talk to your healthcare provider before making any changes, because this diet can drastically reduce your need for medication.
Summary For people who are physically active or want to maintain their weight, a range of 100–150 grams of carbs per day may have benefits. For those aiming to lose weight quickly, going under 50 grams per day under the guidance of a healthcare provider may help.
A low carb diet isn't just about weight loss, it may also improve your health.
For this reason, the diet should be based on whole, unprocessed foods and healthy carb sources.
Low carb junk foods are often unhealthy.
If you want to improve your health, choose unprocessed foods such as:
- lean meats
- healthy fats
Choose carbohydrate sources that include fiber. If you prefer a moderate carb intake, try to choose unrefined starch sources, like potatoes, sweet potatoes, oats, and brown rice.
Added sugars and other refined carbs are always unhealthy options, it’s recommended that you limit or avoid them.
Summary It’s very important to choose healthy, fiber-rich carb sources. A healthy diet includes plenty of vegetables, even at the lowest level of carb intake.
Low carb diets greatly reduce your blood levels of insulin, a hormone that brings the glucose from carbs into the body’s cells.
One of the functions of insulin is to store fat. Many experts believe that the reason low carb diets work so well is that they reduce your levels of this hormone.
Another thing that insulin does is to tell the kidneys to retain sodium. This is the reason high carb diets can cause excess water retention.
It’s common for people to lose a lot of water weight in the first few days on a low carb diet. Some dietitians suggest you might lose up to 5–10 pounds (2.3–4.5 kg) this way.
Weight loss will slow down after the first week, but your fat mass may continue to decrease if you maintain the diet.
One study compared low carb and low fat diets and used DEXA scanners, which are very accurate measures of body composition. The low carb dieters lost significant amounts of body fat and gained muscle at the same time (
Studies also show that low carb diets are particularly effective at reducing the fat in your abdominal cavity, also known as visceral fat or belly fat. This is the most dangerous fat and is strongly associated with many diseases (
If you're new to low carb eating, you’ll probably need to go through an adaptation phase where your body is getting used to burning fat instead of carbs.
This is called the “low carb flu,” and it’s usually over within a few days. After this initial phase is over, many people report having more energy than before, with no afternoon dips in energy that are common on high carb diets.
Summary Water weight drops fast on a low carb diet, and fat loss takes a bit longer. It’s common to feel unwell in the first few days of lowering your carb intake. However, many people feel excellent after this initial adaptation phase.
Before starting the low carb diet, try tracking how many carbs you eat on a typical day and whether they’re healthy or unhealthy. A free app can help.
Because fiber doesn’t really count as carbohydrates, you can exclude the fiber grams from the total number. Instead, count net carbs, using this calculation: net carbs = total carbs - fiber.
If you’re not losing weight or weight loss slows down during the low carb diet, check out these possible reasons why.
One of the benefits of low carb diets is that, for many people, it’s easy to do. You don't need to track anything if you don't want to.
Just eat some protein, healthy fats, and veggies at every meal. Include some nuts, seeds, avocados, and full-fat dairy products. Also, choose unprocessed foods.