Physicians and patients often ask Alison Evert, MS, RDN, CDCES, what percentage of fat, carbohydrates, and protein should comprise their total calorie count each day. Her answer: It depends—it has to be individualized based on an assessment of the person in question, how they eat, and their goals.
“I would say, once again, ask an open-ended question to your patient: ‘What is it that you want to do with your health? Is it glucose management? Is it something to do with improving your lipid profile or blood pressure or weight loss?’” said Evert, University of Washington Medicine Primary Care Clinics.
Evert discussed meal and snack frequency, as well as macronutrients and calories during the mini-symposium Top 5 Nutrition Controversies on Friday, June 3. The session was livestreamed and can be viewed on-demand by registered meeting attendees at ADA2022.org. If you haven’t registered for the 82nd Scientific Sessions, register today to access the valuable meeting content.
Evert said one of the reasons she’s unable to give blanket answers about nutritional questions is because of a lack of hard evidence. Studying diets isn’t as easy as studying medications because of compliance issues with patients who tend to detour from or abandon prescribed eating plans, she said. But there is evidence showing that people with type 2 diabetes eat pretty much the same ratio of macronutrients as the general population, she noted.
Evert cited data from The National Health Examination Survey collected between 1999 and 2016. The survey looked at 24-hour dietary recalls from 44,000 people and found that they consumed about 50 percent of their calories from carbohydrates, 16 percent from protein, and 33 percent from fat. The survey data also indicate that people are eating less sugar over the last 18 years and increasing consumption of whole grains, poultry, nuts, and polyunsaturated fats. Unfortunately, 42 percent of the carbohydrates consumed are coming from low-quality sources like refined grains, fruit juice, and potatoes.
The ADA conducted a rigorous systematic review and concluded that there’s no optimal mix of carbohydrates, proteins, and fats for people with diabetes, Evert said. As for calories, she said the suggested calorie limits from the 1980s are outdated.
“There’s no evidence base that there’s a set amount of calories that works for every person that has a diagnosis of diabetes,” she said.
Teaching individuals “troubleshooting skills” is more important than setting a hard rule about calorie limits and macronutrient ratios, Evert said. And those skills should include using a continuous glucose monitor (CGM), which she called “a game changer.”
“It’s such a wonderful behavior modification tool for people with type 2 diabetes,” she said. “I literally say, ‘You are your own science experiment.’ When patients ask me, ‘What can I eat?’ I say, ‘You tell me. Look and see what happens in that cause-and-effect relationship. What would you do differently next time?’”
Evert is also inundated with questions about meal and snack frequency, with questions that range from whether they should eat three meals and three snacks a day to whether it’s a good idea to skip meals and practice intermittent fasting.
Coordinating meal plans with patients who are taking medications can reduce side effects and optimize clinical outcomes, Evert said. Meal timing can also be vital for patients taking insulin to minimize hyperglycemia and glucose variability.
Not eating breakfast is associated with a higher risk of heart disease, Evert said, while eating breakfast may assist with postprandial glucose management later in the day as long as a person isn’t eating more calories overall. And intermittent fasting appears to be linked to the circadian rhythm in the peripheral organs, so it’s important to find out specifically when patients want to eat, she said.
Another dietitian, Maureen Chomko, RD, CDCES, of Neighborcare Health in Seattle, discussed artificial sweeteners, net carbs, and whether very low-carb eating plans are safe.
Net carbs are calculated by subtracting dietary fiber and sugar alcohols, which are unavailable carbohydrates, from the total carb count of foods and drinks. The British Medical Journal first published the idea of unavailable carbohydrates in 1929, and Dr. Robert Atkins and the Atkins Diet brand popularized the term “net carbs” about 70 years later. Chomko described “net carbs” as a marketing term that prescribes a facade of health onto a product.
Chomko noted that artificial sweeteners are hard to study because they are processed differently in our bodies and typically not consumed in isolation. That said, she cited a systematic review and meta-analysis of randomized controlled trials and cohort studies published five years ago in the Canadian Medical Association Journal that found no significant effect on BMI in people who consumed artificial sweeteners. There were, however, increases in hypertension, metabolic syndrome, type 2 diabetes, and cardiovascular events.
No one knows why this happens, she said.
“The strongest evidence seems to be that artificial sweeteners cause changes in the gut microbiome that lead to decreased glucose tolerance and increase in body weight,” said Chomko, noting that studies have shown that artificial sweeteners change the microbiome in rodents.
The ADA’s position is that there’s not enough evidence to determine whether sugar substitutes definitively lead to long-term reduction in body weight or cardio metabolic risk factors, Chomko noted.
Chomko also cited a review by the National Lipid Association on the effects of very low-carb diets compared to high-carb, low-fat diets in adults with diabetes at one to two years of follow-up. The low-carb diet produced a trend toward increased LDL cholesterol that was not significant due to higher intake of saturated fat. HDL cholesterol increased and triglycerides decreased—not only in very low-carb diets, but also at moderate and low-carbohydrate levels.
“So that might help improve adherence for a patient if they can’t do this very low-carbohydrate diet,” she said. “They can try low-carb or a moderate-carb intake to lower the triglycerides.”
Chomko discouraged low-carb or keto diets for patients using sodium-glucose cotransporter 2 (SGLT2) inhibitors because the diets could lead to glycemic decay. She also said the diets can be dangerous for patients with chronic kidney disease.