Low-carbohydrate (low-carb) diets have gained popularity over the past few years for helping people achieve health benefits like weight loss, managing chronic diseases like diabetes, and feeling better.
Continue reading to learn about carbohydrates, how to get started with a meal plan, and if a low-carb diet is right for you.
Low-Carb Diet Basics
There are many different descriptions of low-carbohydrate diets:
- Very low-carbohydrate or ketogenic diet: 20 to 50 grams carbs per day; some ketogenic diets are less than 30 grams per day
- Low-carbohydrate diet: 130 grams or less of carbs per day
- Moderate-carbohydrate diet: More than 130 grams of carbs per day
- High-carbohydrate diet: 225 grams or more of carbs per day (1)
Curious to know what exactly a carb is? Carbohydrates are found in many foods. Some carbohydrates are more complex, like the ones found in beans, lentils, vegetables, whole grains, nuts, and seeds. Some carbohydrates are simple, like the ones found in sugar, candy, and fruit.
Dairy, like milk and yogurt, contains carbohydrates. Complex and simple carbs found in plants are full of fiber, vitamins, minerals, antioxidants, and polyphenols, which help prevent disease. Carbs found in sweets like soda have no nutrients.
For reference, the following foods contain about 15 grams of carbohydrate:
- ½ a cup of plain, cooked oatmeal
- 1/3 a cup of pasta or rice
- 3 cups plain popped popcorn
- 15 grapes
- 2 tablespoons of raisins
- ½ a cup of beans
- ½ a cup (4 ounces) juice or soda
To learn about the amount of carbs in the foods you commonly eat, look on the nutrition label under “carbohydrate”. It is also important to pay attention to serving size on the label. Something may seem low carb, but you may be accidentally eating several servings!
Meats, cheese, and fats like butter and oil have no carbs. Nuts and avocados have a small amount of carb.
Supporters of low carb diets argue that low-carb diets are healthy. They point out that we have been eating more and more carbs since the 1970s. It was around this time that fat was demonized. Food companies began making low-fat foods, but to make them taste good, loaded them with carbs, especially simple sugars. As people began eating less fat and more carbohydrates, obesity and diabetes rates increased (2).
Low-carb diet advocates claim that eating more carbs causes higher levels of insulin. Insulin, in addition to acting like a key to let blood sugar into your cells, also tells the body to make and store fat (2). Thus, a low-carb diet can help with weight loss.
One benefit of a low-carb diet is eliminating highly processed foods that are loaded with sugar, fat, and calories. These foods contain very few if any nutrients. Eating too many processed foods can increase your weight and risk for diseases like diabetes and heart disease.
A low carbohydrate diet includes lean protein like poultry, seafood, lean cuts of beef and pork, avocados, healthy oils, and nuts. Include lots of non-starchy vegetables like kale, collard greens, swiss chard, asparagus, broccoli, Brussel sprouts, eggplant, tomatoes, beets, and peppers.
Popular Low-Carb Diets
The ketogenic diet, or keto for short, is a popular diet where people restrict their carbs to less than 50 grams a day. Some keto plans are even stricter and only allow 20 to 30 grams a day. The theory behind the keto diet is that by reducing carbs, the body enters ketosis and begins burning fat as a source of energy . While some people find keto helpful to lose weight, remember that a calorie deficit is critical for weight loss.
The Atkins Diet
The Atkins Diet was a popular low-carbohydrate diet in the 1960s. It was developed by Dr. Robert C. Atkins, a cardiologist. Similar to the keto diet, it requires followers to lower the amount of carbs they eat to between 20-40 grams so the body would begin burning fat .
The Atkins diet also uses a term called “net carbs”. Fiber and sugar alcohols are subtracted from total carbohydrates, and this number is called the “net carbs” that followers use while tracking their carbs.
Paleo, or the “caveman” or “Stone Age” diet, focuses on copying the diet our ancestors ate during the Paleolithic era, which was around 12,000 years ago. Practitioners of this diet believe our ancestors followed a hunter-gatherer diet, which was high in fruits, vegetables, nuts, seeds, oils like walnut, coconut, olive, and avocado, meat, fish, shellfish, poultry, and eggs (4).
While this diet doesn’t focus on grams of carbohydrates the same way the keto and Atkins diet do because it eliminates grains, dairy, legumes, potatoes, and refined sugar, all foods that contain carbohydrates, followers of this diet eat less carbs.
The Mediterranean Diet
Like the Paleo diet, the Mediterranean diet focuses more on the quality of the diet than on grams of carbohydrate. It is high in vegetables, fruit, legumes, nuts, and unprocessed grains but low in meat and dairy. Olive oil is a staple, red wine is included, and fish is eaten a few times a week. While fruits, legumes, and unprocessed grains are not low-carb, they are high in antioxidants, fiber, vitamins, and minerals. Added sugars and added fats are discouraged on this diet.
The Mediterranean diet has decades of research to support its health benefits including lowering the risk of developing Alzheimer’s, heart disease, type 2 diabetes, cancer, and Parkinson’s disease (5).
The American Diabetes Association recommends the Mediterranean diet for managing type 2 diabetes.
Foods to Eat
To get started with low-carb dieting, include lots of vegetables, meat, seafood, and some nuts, oils, and seeds. It is important to not only restrict your carbohydrates but make sure the foods you are eating are rich in nutrients.
Vegetables contain few carbohydrates but are packed full of nutrients, antioxidants, and polyphenols.
- Dark leafy greens
- Swiss chard
- Romaine Lettuce
- Brussel sprouts
- Collared Greens
- Green beans
- Bok choy
Some vegetables have more carbohydrates then others but are still low in carbs. One cup of carrots has about 9 grams of carbs, but a 12 ounce can of soda has 35 grams of carbs. Depending on how much you are restricting your carbohydrate, be mindful of the following vegetables:
- Spaghetti Squash
Nuts and Seeds (look for dry roasted to avoid added oils)
Nuts contain few carbohydrates but are full of healthy fats, some protein, and different vitamins and minerals.
- Sunflower seeds
- Pumpkin seeds
- Chia seeds
- Almond butter
Seafood has no carbohydrates and is high in protein and healthy fats.
Meat does not have any carbohydrates and is high in protein.
- Game meat like venison
- Beef (try to buy 100% grass-fed for highest quality beef)
- Organ meat
- Processed sandwich meat such as baloney, pastrami, and salami*
*Avoid if you see added sugar and nitrates on the ingredient label. These foods, while low in carbohydrates, are also low in nutrients. Consider these to be more of a treat then everyday food.
Milk and yogurt both contain carbohydrates, while cheese does not. Lactose, or milk sugar, is lost during processing when cheese is made. Therefore cheese is low in carbs.
- Blue cheese
Oils do not have any carbohydrates.
- Coconut oil
- Palm oil
- Avocado Oil
- Olive Oil
Foods In Moderation
Depending on how many grams of carbohydrates you are eating a day, there are some foods you can still include in your diet, just in limited amounts.
Fruits are a great source of fiber, vitamins, and minerals. Berries are packed full of health-promoting antioxidants. If you are eating low-carb, you can still include fruits, but you need to limit your quantity.
Check the nutrition facts to see how many carbs are in the fruit. One cup of strawberries, for example, contains 9 grams of carbs, while 1 cup of blueberries contains 18 grams. A medium-sized banana can contain 24 grams of carbs or more. That isn’t to say these foods are bad, but if you are restricting your carbohydrates you should be mindful. This is a list of lower-carb fruits:
Like fruit, depending on how many carbs you are eating a day, you don’t need to completely eliminate grains. Whole grains are full of fiber and protein.
- Steel-cut oats
- Plain popcorn
- Whole grain bread
- Brown rice
Beans are full of plant-based protein, fiber, folate, manganese, potassium, iron, and copper. They are rich in phytochemicals, which can help prevent disease (5). However, ½ a cup of black beans has about 14 grams of carbs, so you need to watch your portion size if you are eating beans.
- Black beans
- Kidney beans
- Navy beans
- Cannellini beans
An 8-ounce cup of milk has about 12 grams of carbs. Yogurt can be packed full of sugar, so be careful and always read the label.
Foods to Avoid
Many of the foods listed here are high in carbs, sugar, and unhealthy fats. They may taste good, but they provide no nutrition for you.
- Ice cream
- Sugary cereals
- Regular soda
- White bread
- Refined grains
- French fries
1-Day Low-Carb Diet Meal Plan
- 3 Eggs
- 1 tablespoon coconut oil with
- 3/4 a cup of asparagus
- 3 ounces shredded mozzarella cheese,
- 1 cup strawberries
Nutrition info: 643 calories, 40 grams protein, 13 grams net carbohydrate, 21 grams of carbohydrate, 45 grams of fat
- 3 ounces of salmon
- 1 small avocado, diced
- 1 small tomato, diced
- 1 cucumber, diced
- 1 cup green peppers, diced
- 3 cups mixed salad greens (spinach, baby kale, and arugula)
- Balsamic vinaigrette drizzle
Nutrition info: 519 calories, 29 grams protein, 27 net grams of carbohydrate, 40 grams carbohydrate, 30 grams fat
- 1 tablespoon coconut oil
- 1 tablespoon minced garlic
- 1 small onion, diced
- ½ pound ground turkey
- 3 cups baby spinach
- 8 ounce can tomato sauce
- Black pepper to taste
- 4 colored peppers
- ¼ a cup shredded cheddar cheese
- Preheat the oven to 375. In a medium-size saucepan, heat 1 tablespoon coconut oil over medium heat. Add the minced garlic and diced onions.
- Cook for 5 minutes, or until onion is soft. Add the ground turkey and spinach. Cook until the turkey is brown, then drain. (Spinach will be wilted). Add tomato sauce and stir.
- Add black pepper to taste. Cut the tops off the peppers and stuff with the mixture. Cook for 30 minutes if you like a crunchy pepper or 45 minutes if you like a soft pepper. Sprinkle the tops with cheddar cheese in the last 10 minutes of cooking.
Nutrition facts: 778 calories, 99 grams of protein, 46 grams net carbohydrate, 65 grams of carbohydrate, 19 grams of fat
- 2 tablespoons of nut butter like peanut butter or almond butter
- 1-2 hardboiled eggs
- Turkey or beef jerky
- 1 piece of dark chocolate
- ¼ a cup nuts
- Salmon or tuna pouches, single-serving size
Benefits of a Low-Carb Diet
Studies show low-carb diets help you lose weight and improve blood sugars. A study out of Duke University Medical Center took 84 subjects with obesity and type 2 diabetes. Subjects received either a low-carb (<20 grams of carbs each day) or a calorie-reduced diet for 24 weeks. The low-carb group lost 24 pounds and their A1C, a measure of blood sugar over 3 months, dropped by 1.5%. The calorie-reduced group lost 15 pounds and their A1C dropped by 0.5% (6).
A review of research about low carbohydrate diets and weight loss found that a low-carb diet can help people lose weight more quickly. Those following a low-carb diet lost 12 pounds during the first 6 months compared to 3 pounds in the low-fat group. At 12 months, however, the amount of weight loss between the 2 groups was similar (10).
But following a low-carb diet can help you see weight loss quicker, which can motivate you to stay on track. Remember that if you are trying to lose weight, following your diet consistently is key to maintain your weight loss.
Increased Levels of ‘Good’ HDL Cholesterol
A large review looked at low-carb diet’s effects on cholesterol, LDL (bad cholesterol), HDL (good cholesterol), and triglycerides. On average, the low-carb diet lowered cholesterol by 2.7 mg, LDL by 3.7 mg, increased HDL by 3.3 mg, and lowered triglycerides by 14 mg (7).
Richard D. Feinman, Ph.D., a professor of cell biology at the State University of New York Downstate Medical Center, helped author a large review about low carbohydrate diets and diabetes. He argues that high blood sugar is the biggest concern of diabetes, both type 1 and type 2. Therefore, restricting carbohydrates will yield the biggest improvement of blood sugar for diabetics.
Risks and Side Effects
One side effect of a low-carb diet is known as low-carb flu. You may experience fatigue, headaches, and feeling foggy. Low-carb flu is due to the loss of fluids and salts. Drink plenty of fluids and electrolytes to avoid this. It may be helpful to gradually lower carbs instead of drastically reducing them (8).
A low-carb diet may cause cramping. Like the low-carb flu, cramping is due to loss of fluids and electrolytes like potassium, magnesium, and sodium. Add salmon, eggs, almonds, and mushrooms to increase potassium in your diet (8).
Drastically reducing carbohydrates, especially healthy carbs like fruit, whole-grains, and beans means less fiber. This can cause constipation. Drink plenty of water and eat lots of vegetables, especially dark leafy greens. Almonds are also high in fiber. A bulking laxative, like Metamucil, FiberCon, or Citrucel, can also help (8).
Some new research suggests this diet may increase the risk of heart disease. One prospective study followed Swedish women for almost 16 years. The more closely the women followed a low-carb/high protein diet, the more likely they were to develop heart disease (9).
Research is ongoing to determine the safety and benefits of low-carb diets long term.
- Brown-Riggs, Constance. Low-Carb Diets & Diabetes. Today’s Dietitian, August 2016. https://www.todaysdietitian.com/newarchives/0816p24.shtml
- Feinman, Richard, et al. “Dietary carbohydrate restriction as the first approach in diabetes management: Critical review and evidence base.” Nutrition, Vol 31, January 2015. https://www.sciencedirect.com/science/article/pii/S0899900714003323?via%3Dihub#fig1
- Smithson, Toby, and Warshaw Hope. Very Low-Carbohydrate Diets. Today’s Dietitian, November 2018. https://www.todaysdietitian.com/newarchives/1118p28.shtml
- Amidor, Toby. Paleo: Spotlight on the Paleo Diet. Today’s Dietitian, February 2018. https://www.todaysdietitian.com/newarchives/0218p14.shtml
- Dennett, Carrie. Key Ingredients of the Mediterranean Diet — The Nutritious Sum of Delicious Parts. Today’s Dietitian, May 2016. https://www.todaysdietitian.com/newarchives/0516p28.shtml
- JB. Buse, KS. Polonsky, et al. “The Effect of a Low-Carbohydrate, Ketogenic Diet versus a Low-Glycemic Index Diet on Glycemic Control in Type 2 Diabetes Mellitus.” Nutrition & Metabolism, BioMed Central, 1 Jan. 1970, nutritionandmetabolism.biomedcentral.com/articles/10.1186/1743-7075-5-36.
- Hu, Tian, Mills, Katherine, Yao, Lu, Demanelis, Kathryn, Eloustaz, Mohamed, Yancy, William, Kelly, Tanika, He, Jiang, and Bazzano, Lydia. “Effects of Low-Carbohydrate Diets Versus Low-Fat Diets on Metabolic Risk Factors: A Meta-Analysis of Randomized Controlled Clinical Trials,” American Journal of Epidemiology, vol 176, issue 7, October 2012. https://academic.oup.com/aje/article/176/suppl_7/S44/112289
- “Low-Carb Diet Side Effects,” Diabetes.co.uk, 15 January 2019. https://www.diabetes.co.uk/diet/low-carb-diet-side-effects.html
- Lagiou, Pagona, Sandin, Sven, Lof, Marie, Trichopoulous, Dimitrios, Adami, Hans-Olov and Weiderpass, Elisabete. “Low carbohydrate-high protein diet and incidence of cardiovascular diseases in Swedish women: prospective cohort study,” TheBMJ, June 2012. https://www.bmj.com/content/344/bmj.e4026.full
- Nordmann, Alain, Nordmann, Abigail, Briel, Matthias, Keller, Ulrich, Yancy, William, Brehm, Bonnie, Bucher, Heiner. “Effects of Low-Carbohydrate vs Low-Fat Diets on Weight Loss and Cardiovascular Risk Factors: A Meta-Analysis of Randomized Controlled Trials,” Archives of Internal Medicine, February 2006. https://pubmed.ncbi.nlm.nih.gov/16476868/