Editor's note: This popular story from the Daily Briefing's archives was republished on May 4, 2023.

Writing for the Washington Post/Consumer Reports, Sari Harrar debunks common misconceptions surrounding diet and blood sugar control and offers five tips to help individuals regulate their blood sugar levels. 

Why you care about regulating blood sugar

Currently, around 20% of the 37 million American adults who have diabetes and over 80% of the 96 million who have prediabetes are unaware they have those conditions.

"That's especially concerning, because diabetes and prediabetes also mean a higher risk for heart disease; vision, kidney, and nerve damage; and even some cancers," Harrar writes.

According to Hope Warshaw, a certified diabetes care and education specialist, food can be a tool to help regulate blood sugar, or glucose, levels, underscoring the importance of making the right choices to avoid—or manage—prediabetes and Type 2 diabetes.

In particular, "[a] healthy diet may be especially helpful for older adults.," Harrar notes.

For instance, the Diabetes Prevention Program (DPP) study found that when older participants with prediabetes made healthier food choices, exercised regularly, and lost some weight, they reduced their risk of progressing to Type 2 diabetes by 71% over the 2.8-year study period.

Ultimately, "[t]he goal of following a diabetes or prediabetes diet is to prevent insulin resistance," Harrar writes. "Usually after eating, blood glucose rises and the pancreas releases insulin. Insulin shuttles glucose into the cells, where it's used for energy. Insulin resistance occurs when the pancreas can't keep up with the demand for insulin."

Over time, you make less insulin, and glucose levels remain higher than they should. According to Warshaw, a diet that boosts insulin sensitivity is critical for individuals with prediabetes and Type 2 diabetes. It can also help prevent those conditions in others.

5 tips to regulate blood sugar levels

1. Consume the right kind of carbs

It can be difficult to determine which carbs to eat for glucose control—or how much of them, Harrar notes.

"'Bread is the enemy' is something I've heard throughout my career," said Lisa Jones, a registered dietitian who advises clients with diabetes and prediabetes. "And people newly diagnosed with diabetes say 'I can't have fruit because it has sugar.'"

However, there are different types of carbs. "Research shows that some, like refined flour, potatoes and foods with a lot of added sugars, can rapidly raise blood sugar and increase diabetes risk," Harrar writes. For instance, a 2019 study published in Diabetes Care found that people who cut one sugary drink per day decreased the risk of diabetes by 10%.

"On the other hand, carb-containing whole foods like fruit, beans and whole grains have fiber and can slow the rise in blood glucose after meals," Harrar notes. "Levels don't spike and the pancreas isn't taxed."

Other studies support the benefits of certain carbs. In a Danish study of 55,465 older adults and an Australian study from 2021, researchers found that middle-aged and older adults who consumed around two daily servings of fruit were 36% less likely to develop diabetes over five years compared with those who did not consume fruit.

2. Lose some weight (it doesn’t have to be a lot)

Excess weight increases the risk of diabetes by sending additional fat into muscle cells, making it difficult for the muscles to absorb blood sugar. However, "people with diabetes or prediabetes can get overwhelmed by numbers and think they have to lose a lot of weight," Jones said.

"Really, just small amounts make a big difference," Jones said. For example, losing just 5% to 7% of body weight reduced the risk for diabetes in the DPP study.

Still, "I don't care that someone loses 25 pounds," Warshaw said. "It's better to lose 5, 10 or 15 pounds relative to your size and keep as many pounds off as possible. Gaining back the weight will likely increase insulin resistance again."

3. Eat healthy fats

According to a 2016 study, choosing unsaturated fats—like vegetable oils, nuts, avocado, and fish—instead of saturated fats—like butter or red meat—could lower blood glucose enough to reduce diabetes risk by 22%.

"Fats aren't just carriers of calories, they're the most important structural molecules in the body," said Dariush Mozaffarian, dean of the Friedman School of Nutrition Science and Policy at Tufts University.

4. Consult with a doctor before taking supplements

A 2020 study published in BMJ Open Diabetes Research & Care found that 62% of U.S. adults 65 and older with diabetes take supplements, including cinnamon, bitter melon, fenugreek, and magnesium.

According to NIH, while many manufacturers claim their supplements "support" healthy blood glucose or that say they are "natural diabetes cures," there is minimal scientific evidence that they work.

"My approach is food first," Jones said. "So try cinnamon on whole-wheat toast, in fruit salad or in coffee. And before taking supplements, talk to your doctor," Harrar adds.

5. Skip highly processed diabetes bars and shakes

A 2022 study of over 70,000 people found that individuals who consumed the most ultra-processed foods increased their risk of developing Type 2 diabetes by roughly 80% compared with those who ate the least.

"While products made to manage blood sugar may help, they're highly processed foods, containing protein extracts or isolates, many additives and sugar substitutes," Harrar writes. (Harrar, Washington Post/Consumer Reports, 11/14)