Dominic D'Agostino, PhD. Written By Stephanie Eckelkamp. Reviewed By Zoë Atlas, MPH, RDN. What is a low-carb diet? For example, the authors of the research review define these as: Very low-carbohydrate diets consist of less than 10 percent of total calories from carbs, or less than 50 g per day on a 2,calorie diet.

A keto diet is considered very low-carb. Low-carbohydrate diets consist of less than 26 percent of total calories from carbs, or less than g per day on a 2,calorie diet. Moderate-carbohydrate diets consist of 26 to 44 percent of total calories from carbs, or to g per day on a 2,calorie diet.

High-carbohydrate diets consist of 45 percent or more of total calories from carbs, or more than g per day on a 2,calorie diet. To put things in perspective, the Dietary Guidelines for Americans recommend that 45 to 65 percent of total daily calories come from carbohydrates, which some metabolic health experts consider unnecessarily high.

Here are a few plans: Ketogenic: This very low-carb, moderate-protein, high-fat eating pattern typically consists of 15—10 percent carbs, 10—20 percent protein, and 70—80 percent fat. Often, this equates to less than 50 g of carbohydrates per day —but some plans suggest even lower, around 20 to 30 g per day.

Eating this way causes your body to shift from burning predominantly glucose for fuel to burning fat—a state known as ketosis. Keto tends to be higher in fat and lower in protein than other low-carb plans since protein may be converted to glucose in the absence of carbs, and this may prevent ketosis.

Atkins: This low-carb diet encourages the intake of fiber-rich foods by focusing on net carbs total carbs minus fiber, allulose, erythritol, and half of other sugar alcohols. There are three different Atkins plans: Atkins 20, Atkins 40, and Atkins , which allow you to consume 20, 40, and grams of net carbs , respectively.

While Atkins can be maintained indefinitely, Atkins 20 and 40 are meant to start low to support weight loss and then gradually increase net carbs up to a max of g per day from whole-food sources such as vegetables, fruits, legumes, and whole grains.

South Beach: This modified low-carb diet focused on weight loss has three phases. The initial phase significantly limits sugars and refined carbohydrates and focuses on lean proteins, high-fiber vegetables, and unsaturated fats. The middle phase reintroduces some carb sources fruits, starchy vegetables, whole grains.

The maintenance phase restricts total carbohydrate intake to no more than 28 percent of total calories, or about g per day. Both typically involve avoiding refined sugars, dairy, grains, and legumes.

Whole30 also avoids all forms of added sweeteners and alcohol. Carb Cycling: While not an official diet, a carb-cycling approach refers to eating low-carb or keto most of the time with short periods of higher-carb intake. For example, every week, you might eat keto for six days followed by one day of higher-carb intake 1.

The potential benefits of a low-carb diet People may choose to eat low-carb for a variety of reasons. Weight loss Several studies have found that low-carbohydrate diets promote weight loss better than higher-carb diets in the short term and have similar effects to other dietary approaches over extended periods.

But there are a few potential reasons they may be effective if maintained: Well-formulated low-carb diets e. By reducing carb intake and subsequent elevations in blood sugar, you also decrease insulin secretion.

Insulin is an essential anabolic or storage hormone. When chronically elevated due to a high-carb, high-sugar diet, it can promote the conversion of excess glucose to body fat and make it more challenging to burn stored fat, contributing to obesity and other metabolic consequences.

On the other hand, lowering carbohydrate intake— and pairing the carbs you eat with blood sugar-buffering fiber, protein, and fat—can reduce insulin secretion to healthier levels and counter these effects.

Very low-carbohydrate diets, including ketogenic diets, may also reduce appetite. A preliminary study from suggests that low-carb diets may increase calorie burn during weight-loss maintenance, potentially making it easier to keep weight off.

In the study, people who had lost 12 percent of their body weight were put on a maintenance diet of either high, moderate, or low carbohydrate intake 60 percent, 40 percent, and 20 percent of calories from carbs, respectively.

Compared to the high-carb group, on average, the moderate-carb group burned 91 more calories daily, and the low-carb group burned more calories. Type 2 diabetes and metabolic syndrome Low-carb diets also offer benefits for people with prediabetes or metabolic syndrome MetS, a cluster of conditions that increases diabetes, stroke, and cardiovascular disease risk.

Cardiovascular disease risk Going low-carb may curb some risk factors for cardiovascular disease. Foods to avoid on a low-carb diet In general, the more processed and refined a carbohydrate-containing food is, the more likely it is to spike your blood sugar and negatively impact metabolic health, says registered dietitian Stephanie Greunke, MD, RD.

Foods to eat regularly on a low-carb diet Non-starchy vegetables green beans, cabbage, mushrooms, cucumber, leafy greens, cauliflower, brussels sprouts, broccoli, eggplant, zucchini, tomatoes, onions, bell peppers , fermented vegetables sauerkraut, kimchi, dill pickles , and low-sugar fruits strawberries, blueberries, blackberries, raspberries, kiwis are rich in blood sugar-balancing fiber and metabolism-friendly micronutrients and relatively low in total carbohydrates.

With protein, a good general rule for metabolic health is 20 to 30 grams per meal and enough per day to support your activity levels and health goals typically somewhere between 1.

The potential drawbacks and gray areas of a low-carb diet While there are positive effects of reducing your carb intake, at the same time, some science suggests this eating pattern may have risks.

Inconsistent impact on LDL cholesterol A somewhat gray area is the impact of low-carb diets on LDL cholesterol—high levels of which have been associated with cardiovascular disease and stroke. Constipation when you skimp on fiber Some people complain of constipation on very low-carbohydrate diets like keto.

Difficulty with adherence Some people find it challenging to maintain a low-carb diet for a long period , particularly very low-carb or keto diets—and this poor adherence may be one reason some of the long-term data on low-carb diets for weight loss and cardiovascular health are a bit unclear.

Should anyone avoid going low-carb? People who may need more carbohydrates for optimal health include: Children Nursing and pregnant women due to significantly increased nutrient and caloric demands Very lean, active people since very low-carb diets have the potential to throw certain hormones, such as leptin , out of whack Athletes concerned with speed and performance although there are exceptions, such as elite athletes who have become keto-adapted Due to the restrictive nature of certain low-carb dietary approaches, people with a history of disordered eating should also avoid going low-carb or starting any diet, for that matter without first talking with an appropriate healthcare provider.

Can you be metabolically healthy without being low-carb? Follow these four strategies and learn other healthy ways to eat carbs here : Focus on unrefined, unprocessed carbs rich in fiber and other nutrients supporting metabolic health.

Always enjoy carbs with a source of healthy fat and protein to promote more gradual blood glucose responses think: an arugula salad topped with roasted sweet potato, grilled chicken, chickpeas, and a drizzle of olive oil and vinegar. Go on a quick walk after eating a higher-carb meal—this can significantly lower blood sugar levels compared to standing or sitting in one place.

Check how you respond to specific carbs using a continuous glucose monitor or a fingerstick test and adjust your diet based on that. Some people have different rises in blood sugar after eating the same carb-containing food.

Medically Reviewed. Lynn Grieger, RDN, CDCES. The One It Will Help Those Backed by Early Studies Jump to More Topics.

Epilepsy in Children This is what the ketogenic diet has been traditionally used to treat, as it provides more stable fuel for the brain to act as an anticonvulsant, says Charlotte Hammond, RD, CDE , a nutrition expert in Boulder, Colorado.

Gout One study suggested that because a ketogenic diet has potential anti-inflammatory properties, it may be useful for preventing gout.

Certain Cancers Using the ketogenic diet as one aspect of cancer treatment is certainly gaining traction. Type 1 Diabetes People with type 1 diabetes are insulin dependent.

Eating Disorders If you have a history of an eating disorder like anorexia or bulimia , or disordered eating, you should not be following a restrictive diet; doing so can cause a relapse.

Binge-Eating Disorder BED BED is also an eating disorder, but it warrants being called out specifically here. Thyroid Disorders Tread with caution if you have a thyroid disorder — that includes hyperthyroidism and hypothyroidism — says Fleck.

Editorial Sources and Fact-Checking. Resources Ketogenic Diet. Epilepsy Foundation. October 25, Tinguely D, Gross J, Kosinski J.

Efficacy of Ketogenic Diets on Type 2 Diabetes: A Systematic Review. Current Diabetes Reports. August 27, What Is Metabolic Syndrome? American Heart Association. March 25, Gibas MK, Gibas KJ.

Induced and Controlled Dietary Ketosis as a Regulator of Obesity and Metabolic Syndrome Pathologies. November Moreno B, Crujeiras AB, Bellido D, et al.

Obesity Treatment by Very Low-Calorie-Ketogenic Diet at Two Years: Reduction in Visceral Fat and on the Burden of Disease.

December Gomez-Arbelaez D, Crujeiras AB, Castro AI, et al. Resting Metabolic Rate of Obese Patients Under Very Low Calorie Ketogenic Diet.

February 17, Goldberg EL, Asher JL, Molony RD, et al. ß-Hydroxybutyrate Deactivates Neutrophil NLRP3 Inflammasome to Relieve Gout Flares. Cell Reports. February 28, Zick SM, Snyder D, Abrams DI. Pros and Cons of Dietary Strategies Popular Among Cancer Patients.

November 15, Modified Atkins Diet. November 13, Di Lorenzo C, Coppola G, Sirianni G, et al. Migraine Improvement During Short Lasting Ketogenesis: A Proof-of-Concept Study. European Journal of Neurology. January Planning Your Diet Around Your Migraine. American Migraine Foundation.

December 8, PCOS Health Complications. PCOS Awareness Association. Lee RWY, Corley MJ, Pang A, et al. A Modified Ketogenic Gluten-Free Diet With MCT Improves Behavior in Children With Autism Spectrum Disorder.

Mounting evidence indicates that adherence to a lower-carbohydrate dietary pattern is associated with weight maintenance, improved blood glucose and insulin control, lower blood pressure, reduced markers of inflammation, and a more favorable lipid profile.

Additionally, prior concerns regarding the higher fat and cholesterol content of this dietary pattern are less founded in modern research. The inclusion of a lower-carbohydrate option that meets all essential nutrient requirements aligns with the contemporary movement toward more flexibility and precision nutrition.

Most important, a lower-carbohydrate option positions the Dietary Guidelines for Americans to more accurately reflect the current scientific evidence and more effectively address the metabolic health of the nation.

Further, it has the potential to improve nutrition security by addressing metabolic diseases that disproportionately affect people from historically marginalized racial, ethnic, socioeconomic, and cultural backgrounds.

Given that most American adults are living with at least one diet-related chronic metabolic disease, updating the Dietary Guidelines for Americans to recognize and reflect the poor health status of the general population is prudent and urgent.

Several of the leading causes of death and disability in the U. A cross-sectional study of U. adults conducted from — found that food insecurity increased over time among patients with cardiovascular disease CVD and cardiometabolic risk factors, and was more frequent among those with CVD 4.

In this study, disparities in food insecurity persisted across racial and ethnic groups 4. Another study found that CVD, cancer, and diabetes accounted for half of annual deaths in the U.

The cost of poor cardiometabolic health in America is staggering. According to data from the Government Accountability Office GAO , in , treating diet-related diseases accounted for more than half of total federal healthcare spending 5.

Furthermore, the American Diabetes Association ADA reported that having a diet-related disease drove up individual healthcare costs, with people with diagnosed diabetes incurring medical expenditures that were over twice what the medical expenditures would have been if the person did not have diabetes 8.

The DGAC will also explore whether additional examples of healthy dietary patterns should be developed and proposed based on population norms, preferences, and needs of the diverse individuals and cultural foodways within the U. population 9. Given that a majority of Americans are currently living with at least one diet-related chronic metabolic disease 10 updating the DGA to recognize and reflect the poor health status of the general population, and the even more dire health status of historically marginalized populations, is prudent at this time.

This shift can be facilitated by expanding the current three USDA Food Patterns included in the DGA — Healthy U. Style Pattern, Healthy Vegetarian Pattern, and Healthy Mediterranean-Style Pattern — to demonstrate how they can be followed as part of a lower carbohydrate lifestyle that can improve the health of Americans.

Whereas there is no universally accepted definition for low-carbohydrate diets, it is preferred to define them by their absolute content in grams since variation in caloric intake influences the percent of calories derived from any macronutrient Ketogenic diets, a subset of low-carbohydrate diets, typically consist of less than 50 grams of carbohydrate per day with adequate protein and varying amounts of fat African Americans and Hispanic Americans are disproportionately affected by overweight and obesity in the U.

Weight loss was significantly more pronounced as participants further restricted carbohydrate intake and was more prominent among participants who were overweight or obese at baseline population manage weight and are a promising solution to race and ethnicity-associated weight disparities.

With U. obesity prevalence being Carbohydrate restriction 26 and weight control can help reduce the risk for type 2 diabetes In , African Americans died from diabetes at a rate of 1.

Further, between and , compared with persons with high income, the relative percentage increase in diabetes prevalence was 40, The ADA, the leading public health authority on diabetes in the U.

Nearly half of adults in the U. Elevated blood pressure increases risk for heart disease, heart attack, and stroke, and in , more than half a million deaths in the U. were attributable to hypertension Even better results have been demonstrated with lower carbohydrate intakes 32 , Strategies to reduce risk for cardiovascular-related diseases are warranted, and mounting evidence indicates low and moderate carbohydrate restriction is associated with lowering blood pressure in adults 14 , Low-carbohydrate dietary patterns have also been demonstrated to improve lipoprotein profiles 15 , thereby reducing risk for CVD.

Significant improvements in triglyceride levels among healthy people 14 , 16 or the general public-those with at least one chronic disease - 20 , 26 , 34 , 35 have been consistent across both observational and controlled studies when people follow low carbohydrate dietary patterns.

NAFLD is the most common cause of chronic liver disease in western countries 37 and disproportionately affects Hispanic Americans Ketogenic diets have been demonstrated to promote metabolic benefits in people with NAFLD 37 , Effects have been attributed to improved liver fat metabolism and beneficial shifts in gut microbial composition This is of importance when considering that the majority of adults in the U.

Data from randomized clinical trials indicate low-carbohydrate versions of currently recommended dietary patterns are safe and effective in reducing risk factors associated with chronic diseases.

Another trial demonstrated that compared with the traditional Dietary Approaches to Stop Hypertension DASH diet, a modified version that was lower in carbohydrate and higher in fat lowered blood pressure to the same extent as the traditional DASH diet, and reduced plasma triglyceride and VLDL concentrations without significantly increasing LDL cholesterol These are just a small sampling of the extensive peer-reviewed published studies demonstrating that low-carbohydrate eating patterns are safe and highly effective at promoting weight loss and improving metabolic health The results of these clinical investigations demonstrated that low-carbohydrate versions of DGA-recommended dietary patterns are an acceptable, if not preferred, means of managing chronic disease.

Other studies have also demonstrated that low-carbohydrate diets can fit into a variety of dietary preferences. In a three-year observational study conducted among Japanese outpatients with type 2 diabetes, a moderately low-carbohydrate diet resulted in improved blood lipids and glucose control Table 1 shows the current DGA Healthy U.

Dietary Pattern. The proposed Lower-Carbohydrate Pattern maintains the 1,kilocalorie level of the eating pattern, with a decrease from six to one ounce equivalent per day from grains and 3 to 1.

The proposed Lower-Carbohydrate Pattern could help Americans achieve a lower-carbohydrate lifestyle that fits within the RDA for carbohydrate, fits into the USDA Thrifty Food Plan, and is associated with weight management 14—16 , improved blood glucose and insulin control 17 , 18 , lowered blood pressure 14 , 15 , and a more favorable lipid profile 14 , Healthy U.

The inclusion of a lower-carbohydrate option that aligns with the current scientific evidence and fits within existing dietary patterns will help the DGA more effectively target the spiraling crisis of poor metabolic health in the nation.

Yet, food insecurity and diet-related diseases are largely preventable, if we follow the best science and prioritize the health of the nation 9.

All authors listed have made a substantial, direct, and intellectual contribution to the work and approved it for publication. Funding support for this publication was provided by an unrestricted grant from Simply Good Foods USA, Inc. JC is an employee and shareholder of Simply Good Foods USA, Inc.

Simply Good Foods owns Atkins® and Quest Nutrition®, brands that sell low-carbohydrate food products. JV is a co-founder and has equity in Virta Health; serves as a scientific advisor for Simply Good Foods and receives royalties from books discussing the science of low-carbohydrate eating patterns.

The authors declare that this study received funding from Simply Good Foods USA, Inc. The funder had the following involvement in the study: helped write the article and design and analyze the dietary pattern modelling. All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers.

Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

USDA, FNS.

Further, the C-peptide elevation in the LCG was found to be associated with the secretion of inflammatory markers. The LCG also reportedly displayed significantly lower serum bicarbonate and serum albumin levels than the RCG.

Investigators noted that these lower levels are considered signs of metabolic acidosis. These factors may impact the generalizability and reproducibility of the study results.

In addition, the self-reported food diary may have introduced a study bias. In fact, US reports indicate that the prevalence of metabolically healthy adults is low, 12 even for those within a normal BMI range.

While the researchers acknowledged some of these potential limitations, other possible confounders were not mentioned and may have influenced the results. Lifestyle and environmental factors may present confounders in this study. Researchers noted that the physical activity amounts did not vary significantly between groups; however, researchers did not include other potentially confounding factors for the study population such as socioeconomic status, smoking habits, and environmental toxicant exposures, all of which have been suggested to impact metabolic health.

Complete diet composition and dietary habits were not recorded for the participants in this study. Only total calories and carbohydrates were measured, recorded, and used for analysis. The types and quality of carbohydrates consumed e. were not distinguished. Also, no other macronutrients or nutritional patterns e.

were recorded. Other research studies have indicated that complete nutritional patterns are essential for more informative assessment of health impacts. Interestingly, the researchers in this study used the Seidelmann et al cohort study on low-carbohydrate intake and mortality to affirm their observation of a U-shaped effect of more potential negative health impacts seen in both the low and high-carbohydrate intake groups.

However, researchers did not mention that while the overall results of the Seidelmann et al study did indicate that both low and high-carbohydrate consumption conferred greater mortality risk than moderate-carbohydrate intake, further analysis indicated that those results varied by the source of the exchanged macronutrients.

Investigators in the Seidelmann et al study found that participants who replaced carbohydrates with plant-based substitutions decreased mortality risk while animal-derived fat and protein substitutions were associated with an increased mortality risk.

have suggested that substitution of carbohydrates by mainly saturated fats may negatively impact lipid profiles 20 while replacing carbohydrates with poly or monounsaturated fats may improve lipid profiles to support metabolic health.

In the Al-Reshed et al study, the LCG and RCG had similar total calorie intakes; therefore, highlighting the carbohydrate substitutions would be important for a more complete assessment.

This would be extremely important for this Kuwait-specific population due to recent reporting that suggested a link between suboptimal dietary intake patterns i.

In addition, the timing of carbohydrate consumption may also play a role in metabolic health and may also influence glucose and insulin-related biomarker testing, as seen in previous research. While the Al-Reshed et al study continues the important diet and health conversation, the title and conclusions in this cross-sectional study are extremely misleading when many lifestyle, demographic, and nutritional factors were not recorded, assessed, or available for consideration.

Considering the entirety of these factors and emphasizing a rainbow of nutrient-dense, plant-based foods to ensure the adequate intake of a variety of healthy micro and macronutrients are core components when developing a personalized approach to optimal health and wellness.

Type 2 Diabetes and Ketogenic Diet. After eating a low-carb diet, more than half the participants — five men and four women — saw their metabolic syndrome reversed even though they were fed diets that intentionally contained enough calories to keep their weight stable.

That was clearly not the case here," Volek said. Obviously, quality of diet matters because quantity is locked down in this experiment. The study appears in the Journal of Clinical Investigation Insight. Over about four months, each study participant ate three month-long controlled diets — high-carb, moderate-carb and low-carb — with a two-week break between diets.

The order in which the participants ate the diets was randomly assigned. After eating the low-carb diet, the participants had a variety of significantly improved health measures, particularly lower triglycerides and improved cholesterol readings. Despite the fact that the low-carb diet contained 2.

Although it may be exciting to see pounds on the scale drop, the ability to keep losing weight or even maintain any weight loss becomes harder, because cravings to eat rise while the body more readily stores those calories as fat.

The purpose of the BMJ study was to see if different levels of carbohydrate in the diet could prevent these metabolic changes from occurring, so that any weight lost might stay off. The next phase randomly assigned the participants who achieved this weight loss to one of three test groups:.

Total calories were adjusted up or down to prevent any weight changes in each participant. All meals were provided to the participants during the weight loss phase and throughout the week test phase.

The types of foods in each diet group were designed to be as similar as possible, but varying in amounts: the high carbohydrate group ate more whole grains, fruits, legumes, and low fat dairy products.

In contrast, the low carbohydrate group ate more fat but eliminated all grains and some fruits and legumes. Participants followed the diets for 20 weeks and total energy expenditure was measured.

During the 20 weeks, the participants in all groups maintained their weight and there was minimal difference in secondary measures including physical activity and resting energy expenditure factors that could independently increase total energy expenditure. David Ludwig , professor in the Department of Nutrition at the Harvard T.

Chan School of Public Health, who led the study with Dr. In a review featured in Science magazine the same week as the BMJ study, Dr. Ludwig discussed the controversy over specific fat-to-carbohydrate ratios in maintaining a healthy weight and lowering disease risk.

Willett, and other experts on the subject agreed that by focusing mainly on diet quality—replacing saturated or trans fats with unsaturated fats and replacing refined carbohydrates with whole grains and nonstarchy vegetables—most people can maintain good health within a broad range of fat-to-carbohydrate ratios.