Use evidence to debunk myths about net carbs, artificial sweeteners, low-carb diets



Chomko M.2-BM-MS02. Presented at: American Diabetes Association Scientific Sessions; June 3-7, 2022; New Orleans (hybrid meeting).

Disclosures: Chomko reports no relevant financial disclosures.

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NEW ORLEANS — Providers should use evidence-based recommendations to educate people with diabetes on misconceptions surrounding net carbohydrates, artificial sweeteners and very low-carbohydrate diets, according to a speaker.

Maureen ChomkoRDN, CDCES, a dietitian and diabetes care and education specialist at Neighborcare Health in Seattle, said methods for calculating net carbohydrates, the effects of artificial sweeteners on health, and safety concerns with very low-carbohydrate eating patterns are common areas where people with diabetes have questions for providers. Chomko discussed those three nutritional topics during a presentation at the American Diabetes Association Scientific Sessions.

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Stop counting net carbohydrates

Counting net carbohydrates was a concept popularized by the Atkins diet about 20 years ago, according to Chomko. The Atkins diet encourages people to track net carbohydrates by subtracting the amount of fiber and sugar alcohol consumed from total carbohydrates.

However, all fiber is not equal, according to Chomko. Insoluble fiber does not contribute carbohydrate or calories, and no definitive evidence demonstrates how many carbohydrates and calories are digested from soluble fibers.

Chomko said sugar alcohols can also affect postprandial blood glucose response, contrary to claims from many food manufacturers. The content of the sugar alcohol varies based on the ingredient used in the food product as well as by country.

“The term ‘net carbs’ assumes the blood glucose response from all fibers and sugar alcohols is going to be easily predicted and will have the same exact effect on everyone,” Chomko said. “In reality, the effect is going to differ based on a lot of factors that depend on each individual.”

Chomko said calculating net carbohydrates is not recommended due to a lack of evidence supporting the practice, especially among those using diet and exercise, or nonmedical eating plans. People with diabetes should instead look at total carbohydrates and monitor preprandial and postprandial glucose if they are eating foods high in fiber or sugar alcohols.

Evidence weak on artificial sweeteners

Negative headlines in the media have produced numerous misconceptions about the dangers of artificial sweeteners, according to Chomko. However, much research on artificial sweeteners includes limitations, making it difficult to pinpoint them as the cause for detrimental health effects. Artificial sweeteners affect metabolism differently, they are not consumed in isolation but with other ingredients within the same product, and it is not possible to isolate the effects of artificial sweeteners within complex diets

In a systematic review and meta-analysis published in the Canadian Medical Association Journal In 2017, the effects of artificial sweeteners on metabolic health were mixed. Randomized controlled trials found artificial sweeteners had no effect on BMI, whereas cohort studies found these sweeteners were associated with a slight increase in BMI as well as increases in hypertension, metabolic syndrome, type 2 diabetes and cardiovascular disease. However, those associations were not confirmed in randomized controlled trials and may be influenced by publication bias, Chomko said.

“The available studies don’t provide proof that artificial sweeteners are beneficial for weight management or the prevention of diabetes,” Chomko said. “But as far as the risks of artificial sweeteners, it’s not possible based on the available data that we have to establish a link between artificial sweeteners and the risks we hear about.”

When discussing artificial sweeteners, providers should ask patients about their concerns and address misinformation, according to Chomko. In addition, since artificial sweeteners might have potential adverse effects, providers should encourage people to substitute water for other beverages using open-ended questions and shared decision-making techniques.

Very low-carb diets safe for most short term

Multiple studies have shown benefits of very low-carbohydrate and ketogenic diets for people with diabetes up to 1 year. In a review published in Diabetes, Metabolic Syndrome and Obesity in 2022, people with diabetes on a very low-carbohydrate or ketogenic diet have greater weight loss and larger reductions in glycemia, HbA1c, and insulin and medication requirements up to 6 months compared with people not restricting carbohydrates. Up to 12 months, the reductions in insulin and medication requirements persist for those on a low-carbohydrate or ketogenic diet. However, the dietary pattern provides no benefits after 1 year.

“We want to understand why our patients want to follow this diet,” Chomko said. “If it’s they want to reduce their insulin or medication requirements, we learned that it works for up to 1 year. We also want to know how they’re going to do the diet.”

Chomko added that it is crucial to understand the background of the person wanting to start a low-carbohydrate diet, as it may not be safe for everyone. According to a scientific statement from the National Lipid Association, adults with type 2 diabetes on a very low-carbohydrate diet had a trend toward increasing LDL cholesterol, but also improvements in HDL cholesterol and triglyceride levels.

“In the population with diabetes wanting to try a ketogenic diet, we want to pay special attention to those with a family history of CVD or if they have a known dyslipidemia,” Chomko said. “We want to check a baseline lipid panel and a follow-up lipid panel after 1 to 3 months to make sure the LDL cholesterol hasn’t risen too much.”

For people using diabetes medications, the risk for hypoglycemia is increased if doses of insulin and sulfonylureas are not reduced. SGLT2 inhibitors should not be used while on a very low-carbohydrate or ketogenic diet due to the risk for euglycemic diabetic ketoacidosis.

The safety of a very low-carbohydrate diet for people with diabetes and chronic kidney disease varies. There may be safety concerns for a person who does not keep protein intake at 10% to 35%, Chomko noted. Additionally, risks must be considered for people with stage 4 or 5 CKD. Although there is very limited data on very low-carbohydrate diets and renal function, impairment of urinary ketone excretion and electrolyte imbalances may occur.

“Very low-carbohydrate and ketogenic diets are safe for most people with diabetes in the short term, as long as we are adjusting their medications and monitoring their labs,” Chomko said. “Long-term data is very scarce after about 2 years in this specific population. We want to assess the goals of our patients and find out if this is a good solution for them.”


  • Azad MB, et al. CMAJ. 2017;doi:10.1503/cmaj.161390.
  • Kirkpatrick CF, et al. J Clin lipidol. 2019;doi:10.1016/j.jacl.2019.08.003.
  • Kumar NK, et al. diabetes metab syndrome Whether it. 2022;doi:10.2147/DMSO.S292742.

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