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Low-carb vs keto: What's the difference and which is better?
While they both restrict carb intake, that’s where the similarities end. Here’s a look at key differences, including which one is likely best for weight loss, diabetes and more.
Walk into a grocery store these days, and what do you see? Lots of labels saying “low-carb” or “keto-friendly.” The same is true of restaurant menus. The promise of weight loss has been the driving force behind promotions like these.
That doesn’t surprise Lauren Spradling, RD. She’s a health and wellness coach at Real Appeal with Rally, part of Optum, in Chicago. “Doesn’t everybody want an easy fix?” she asks.
These eating plans weren’t originally intended for everybody, though. In fact, they were created to address medical problems, say Spradling. The keto eating plan is low in carbs. But it’s very different from the low-carb plan for people with type 2 diabetes.
Before you toss out your pasta, Spradling says, there are a few things you should know so that you can meet your goals in a healthy way.
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What are carbohydrates?
Let’s start with the basics. According to the American Heart Association,1 food has three types of carbs: sugars, starches and fiber. Carbs are either simple or complex.
Simple carbs are digested quickly and raise your blood sugar quickly too. Simple carbs are essentially refined sugars — think cookies, donuts, cakes, candy and other sweets. They give you calories, but don't have any real nutritional value. However, there are also simple sugars in healthy foods, such as apples, bananas, sweet potatoes or yogurt. These contain vitamins, minerals and fiber that are good for us.
Complex carbs are digested more slowly. So they supply a steady release of sugar into the body instead of a rush. Unrefined whole grains — such as brown rice, barley, quinoa or oatmeal — have important nutrients and are rich in fiber. Fiber helps your whole digestive system function better and It makes you feel full. Refined grains, such as white flour and white rice, have been processed. That removes nutrients and fiber, making them less nutritious choices.
How many carbs should most of us eat?
Most healthy adults can follow the Dietary Guidelines for Americans.2 It offers the following breakdown of nutrients per day:
- Carbs: 45% to 65%
- Protein: 10% to 35%
- Fats: 20% to 35%
The guidelines give a range for many reasons. Different people do better with different amounts. It depends on:
- How active you are
- Your age
- Whether you’re pregnant or not
- Your health problems
Most Americans have eating patterns within these ranges.3 To find out where you land, you can use a food tracker like MyFitnessPal. When you enter what you eat, it will figure out the percentages for you. (Get more healthy eating tips.)
What is “low-carb”?
Typically, doctors suggest low-carb eating for medical problems like type 2 diabetes, polycystic ovary syndrome and even acne. A low-carb eating plan may also be helpful for people with heart disease and high blood pressure.
There’s no official definition of a low-carb plan.4 But in general, it’s made up of:
- Carbs: 10% to 30%
- Protein: 40% to 50%
- Fats: 30% to 40%
Some experts say that most people would do well following a low-carb eating plan.
What is “keto”?
When the body needs fuel, it uses glucose (sugar) first. Sugar comes from carbohydrates in food. The goal of a true keto eating plan is to have the body use ketones instead. This is a type of fuel that the liver produces from stored fat when there’s not enough sugar in your blood. Most low-carb plans focus on protein. But a keto plan centers on fat.
The keto eating plan was first designed to help ease seizures in people with epilepsy. And it worked well. Today, studies are looking at how it may help with medical problems that affect the brain and muscles. Examples of these include Alzheimer’s disease and multiple sclerosis. (This is a disease of the central nervous system.)
The keto eating plan can lower blood sugar levels. So it may also be good for people with diabetes or insulin resistance. It may also work for people who have obesity.5
The daily intake of a keto eating plan is broken down this way:5
- Carbs: 5% to 10%
- Protein: 30% to 35%
- Fats: 55% to 60%
The keto eating plan includes a high amount of fats. So, fats must be eaten at each meal. Some healthy unsaturated fats are allowed. They include nuts, seeds, avocados, tofu and olive oil. And some unhealthy saturated fats are allowed, too. These include coconut oil, lard, butter, red meat and full-fat dairy.
That’s why there’s some debate among health professionals about this eating plan. Eating too much saturated fat can raise your cholesterol. And this can raise the risk of heart attack and stroke.
It’s important to know that keto is a bigger shock to the system than low-carb. Spradling says that some programs put patients in the hospital for two days when starting them on a keto plan. This is so they can watch them for side effects. These include nausea, vomiting, headache, feeling tired, dizziness, insomnia and constipation. These symptoms are sometimes called “keto flu.” Typically, they get better in a few days or a few weeks.4
Spradling says there isn’t enough research for her to suggest this way of eating for the average person.
“Always talk to a doctor and a registered dietitian before you make a big change in how you eat,” she says.
To find in-network experts, check with your insurance company. Look on its website or call its customer service line. Be sure to ask for a registered dietitian or a registered dietitian nutritionist. Those titles mean they’re certified in this area of expertise.
What’s the best way of eating for you?
Eating healthier is a great goal for anyone. But everyone’s different. Going on a low-carb or keto eating plan can do more harm than good for some. For instance, people with kidney problems shouldn’t take in too much protein. And if you have heart problems or don’t have a gallbladder, don’t eat more fat.
The best way to eat? Choose foods that work with your health goals. Find a plan that you can stick with for a long time, says Spradling. That may or may not be a low-carb or keto eating plan. For instance, if you want to lose weight, there are easier ways to go about it.
A registered dietitian (RD) can help you make simple tweaks to improve how you eat. And you can still enjoy the foods you love most. “Can you have cake at a party? Yes. Can you have coffee at breakfast? Yes. There’s no such thing as a ‘bad’ food, except one that has spoiled or expired,” Spradling says.
“An RD can help you find a way of life that works for you so you’re getting the nutrients you need. And you’re happy and content.”
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- American Heart Association. Carbohydrates. Last reviewed April 16, 2018. Accessed August 5, 2022.
- USDA. Dietary guidelines for Americans, 2020–2025, page 133. Published December 2020. Accessed August 5, 2022.
- National Center for Health Statistics. Dietary intake for adults aged 20 and over. Last reviewed September 6, 2022. Accessed September 7, 2022.
- National Library of Medicine. Low carbohydrate diet. Last updated July 11, 2022. Accessed August 5, 2022.
- National Library of Medicine. Ketogenic diet. Last updated June 11, 2022. Accessed August 5, 2022.
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