Maybe you have a neighbor who went on a low-carb diet plan and lost a lot of weight. Or you heard about a celeb who did it for a role or to lose post-pregnancy weight. Whatever your motivation, some believe a low-carb diet is the magic solution for weight loss. If you’re curious about if a low-carb diet can work for you and you want to start one, you’re in the right place.
But does it really work? Yes, but research is mixed when comparing low-carb to low-fat diets.
Does a Low-Carb Diet Work?
According to a 2020 review in the journal BMJ, both low-carb and low-fat diets had similar results at six months regarding weight loss and reduction in blood pressure. And low-carb diets had less of an effect on lowering LDL (“bad”) cholesterol than low-fat diets did. Low-carb diets did seem to raise HDL (“good”) cholesterol, though, whereas low-fat diets did not. A 2022 meta-analysis in Frontiers in Nutrition also found similar results for both low-carb and low-fat diets regarding lowering risk factors for heart disease.
But a 2024 review article in Frontiers in Nutrition found evidence suggesting that lower-carbohydrate dietary patterns of less than 130 g per day of carbohydrate seem to result in more favorable effects on average weight loss and risk factors for cardiovascular disease when compared with low-fat dietary patterns.
And a 2024 systematic review and meta-analysis in Diabetes, Metabolic Syndrome and Obesity found that a low-carb diet was more effective than a low-fat diet at improving weight loss, HDL cholesterol and triglycerides.
Some low-fat diets are also low in healthy fats, which may be a reason the ones included in the review articles fell short in improving markers for heart disease. Regardless of what type of eating pattern you choose, including enough heart-healthy fats—like what you find in the Mediterranean diet—is imperative.
Reasons to Start a Low-Carb Diet
Weight loss is the prime reason people go on low-carb diets, says Cassie Bjork, RD, owner of Redefined Weight Loss. “Then there’s the added benefit of reduced sugar cravings. Since carbs turn to sugar in the body, eating fewer carbs can reduce sugar cravings and helps with weight loss.”
But simply cutting carbs does not guarantee you’ll lose weight. Balanced meals are important to ensure you’re getting the nutrients your body needs to stay healthy and feel satisfied.
“Following a low-carb eating plan does not always result in weight loss. No matter what eating plan you’re following, you need to make sure that you’re taking in a diet that provides enough nutrients—protein, fat, carbs, fiber, vitamins, minerals—to keep your body properly fueled,” says Amy Gorin, M.S., RDN, owner of Plant-Based with Amy in Stamford, Connecticut. “And, of course, make sure that you’re not taking in excess calories that could ultimately lead to weight gain.”
The key is to start a low-carb diet responsibly. That doesn’t mean noshing on all the cold cuts, steaks and cheese your heart desires. Nor does it mean that carbs become the enemy. You can—and should—still eat them.
Depending on the program, how many carbs you’re advised to eat in a day varies widely. At EatingWell, we recommend that on a low-carb diet, you get about 40 percent of your calories from carbs—that’s at least 120 grams of carbs total per day. That amount helps you maintain a balanced diet and get all your nutrients in. It’s also more doable than following super-low-carb diets. Their stringency can make them too difficult (and not fun) to follow. What you eat should bring you joy.
With that said, if you’re on a low-carb diet to help manage your diabetes, then working with your healthcare practitioner, registered dietitian or diabetes educator is your best option. They’ll recommend how many carbs you should be eating in a day and give you guidelines on how to count them.
Low-Carb Basics
It’s important to know which foods have carbs, then build your plate based on this knowledge.
Grains, like bread and rice, are a top source of carbs, along with starchy veggies, like potatoes and corn, and legumes like kidney beans. Fruits and milk are also big sources of carbs. Nonstarchy veggies like leafy greens, broccoli and bell peppers have some carbohydrates, but typically aren’t big sources for most people. Protein (chicken, fish, seafood, beef, eggs) and fats (butter, oil) do not contain carbs.
Keep whole grains, dairy—like plain yogurt and milk—fruit and veggies in your diet. “Whole grains, fruit and vegetables provide fiber, which can keep you satiated and may help lower cholesterol,” says Gorin.
Instead of cutting out all carbs, Gorin recommends reducing the types of carbs that aren’t healthy, such as added sugar and refined carbs—things like cookies, soda and sugary cereals. Rather than sweetening your oatmeal with maple syrup, use fruit. A dollop of almond or peanut butter on a sweet potato with dinner can replace brown sugar.
One mistake is forgetting to add healthy fats to your meals. “A lot of people think that low carb means eating steaks all day long, but an often overlooked component is getting plenty of healthy fats,” says Bjork. “Healthy fat keeps you full and will take the place of some of the carbs you used to be eating.”
Not including enough healthy fat is one of the main reasons people get hungry and don’t stick to a low-carb diet—the other reason is lack of fiber, which also contributes to satiety. Examples of healthy fats include avocado, nuts and seeds and olive oil.
How to Put a Low-Carb Diet Together
Make sure to space out your carbohydrates throughout the day, says Gorin. Carbs provide glucose, which is the fuel your brain runs on, so this will help you feel on top of your game and prevent that brain fog feeling.
When building your plate, Gorin recommends a meal with four components: protein (like chicken and salmon), healthy fat, a fruit or nonstarchy vegetable and a whole grain or starchy vegetable. If you’re limiting carbs, you might have a half-cup of brown rice, rather than a whole cup, or a small sweet potato, instead of a large one.
How to Count Carbs
If you’re aiming for a certain number of carbs per day, here are some general guidelines for estimating the number of carbs in certain food groups.
- Starch (grains, beans, starchy veggies) and fruits contain around 15 grams of carbohydrates per serving.
- Milk has 12 grams per serving.
- Nonstarchy veggies (like leafy greens, broccoli and green beans) have around 5 grams of carbohydrates per serving.
- Meats, fats and oils contain zero grams of carbs.
A food diary app (like MyFitnessPal or Lose It!) can also help you keep track of your daily carb intake. It may feel annoying to keep track of carbs at first, but with practice, you’ll quickly get an idea of how you like to divvy them up in your meals—and soon it’ll become second nature and you won’t have to count anymore.
Avoid Going Too Low
While a low-carb diet might help with weight loss in the long run, you don’t want to go too low. Make sure to still consume carbs from healthy sources, like fruits, vegetables and whole grains.
The Bottom Line
A low-carb diet is a good choice for some people. Going too low with your carbohydrate intake, however, can leave you feeling lethargic, brain-foggy and unsatisfied. You may also become constipated due to a lack of fiber. Before diving into a low-carb diet, do your research—learn what high-carb foods to replace with lower-carb options, and how you can eat to reach your goals while still feeling satisfied and enjoying eating.