The term “low carbohydrate” can cause confusion. A low-carb dietary pattern has not been defined by the U.S. Department of Agriculture, and its interpretation varies in the scientific literature. However, many experts consider a low-carb diet to be under 130 grams per day, which is consistent with the Dietary Reference Intake for carbohydrates (1). In fact, a strong body of research shows limiting intake to no more than 130 grams per day, or less than ~25% of total daily calories*, promotes a variety of positive metabolic outcomes (2-3).

Meanwhile, an intake of less than 50 grams of carbohydrate per day is considered “very low carbohydrate,” and most adults enter a state of nutritional ketosis at this level of carb restriction (4). During this state, the body relies primarily on fatty acids and ketone bodies produced from fat stores for energy rather than glucose.

How does a low-carb diet work?

Consuming carbohydrates triggers the release of insulin into the bloodstream. Insulin, in turn, both inhibits the breakdown of fat for energy and promotes fat storage (5). Alternatively, restricting carb intake enables the body to tap into fat as its primary fuel source, prompting the breakdown of body fat. For this reason, a low-carb eating pattern may optimally promote weight loss.

However, the benefits of a low-carb diet extend beyond weight management. The increased use of fat for fuel has a positive influence on a range of other metabolic processes, including cholesterol metabolism, glycemic control, appetite regulation, and inflammation.

Patients can choose from different low-carb eating plans to best meet their needs and preferences. Learn more about Atkins 20®, Atkins 40®, and Atkins 100®.

*Based on a 2,000 calorie diet


  1. National Academies of Sciences, Engineering and Medicine. 2005. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press.
  2. Cliff J, Harvey C, Schofield GM, Zinn C, Thornley SJ, Crofts C, and Merien FLR. Low-carbohydrate diets differing in carbohydrate restriction improve cardiometabolic and anthropometric markers in healthy adults: A randomized clinical trial. PeerJ. 2019. DOI 10.7717/peerj.6273
  3. Hyde PN, Sapper TN, Crabtree CD, LaFountain RA, Bowling ML, Buga A, Fell F, McSwiney FT, Dickerson RM, Miller VJ, Scandling D, Simonetti OP, Phinney SD, Kraemer WJ, King SA, Krauss RM, Volek JS. Dietary carbohydrate restriction improves metabolic syndrome independent of weight loss. JCI Insight. 2019;4(12):e128308.
  4. Volek JS, Feinman RD. Carbohydrate restriction improves the features of metabolic syndrome. Metabolic syndrome may be defined by the response to carbohydrate restriction. Nutr Metab. 2005.;2:31.
  5. Jensen MD, Caruso M, Heiling V, Miles JM: Insulin regulation of lipolysis in nondiabetic and IDDM subjects. Diabetes 1989, 38(12):1595-1601.