June 7, 2023 – Heads-up, type 2 diabetes patients: Researchers in a new study found that eating a low-carb breakfast was linked to a smaller spike in blood sugar after the meal, as compared with eating a low-fat breakfast. Eating a low-carb breakfast was also followed by steadier blood sugar levels throughout the rest of the day.
These findings are from a 3-month study in 121 patients with type 2 diabetes in Canada and Australia.
Half of the people in the study were randomly placed in the intervention group — the low-carbohydrate breakfast — and the other half were placed in the control group.
People in the intervention group were advised to eat a low-carb breakfast, with 25 grams of protein, 8 grams of carbohydrates, 37 grams of fat, and about 450 calories.
They also received eight to 12 recipes for such a breakfast from a registered dietitian. Most of these breakfast recipes contained two to three eggs — for example, an omelet with cheese, or fried eggs with bacon.
Patients in the control group were given advice about eating a low-fat breakfast with about 20 grams of protein, 56 grams of carbohydrates, and 15 grams of fat, but also with about 450 calories.
They also received eight to 12 recipes, but for a low-fat breakfast, which had no or minimal eggs. (For context: One such breakfast consisted of a small blueberry muffin and a small plain Greek yogurt.)
The study showed that if the first meal of the day for people with type 2 diabetes is low-carb and higher in protein and fat, then high blood sugar (hyperglycemic) swings can be reduced, said lead author Barbara Oliveira, PhD, from British Columbia.
"Having fewer carbs for breakfast not only aligns better with how people with type 2 diabetes handle glucose throughout the day," she noted, "but it also has incredible potential for people with type 2 diabetes who struggle with their glucose levels in the morning."
It can be easier to make a small adjustment to the carb content of a single meal rather than the entire diet, she said.
It is very important for patients with type 2 diabetes to have blood sugar levels that are well-controlled, to reduce the risk of complications such as those affecting the eyes, the kidneys, and the heart.
Consuming a low-carb breakfast could be a simple way for people with type 2 diabetes to manage the spike in blood sugar after a meal and to reduce the ups and downs in blood sugar levels throughout the day.
Effect of Cutting Carbs at Breakfasts
The researchers recruited people for the study with online ads in three provinces in Canada and four states in Australia, and they did the study from one site in British Columbia and one in New South Wales, Australia.
The people who took part in it had an average age of 64, and 53% were women.
On average, they weighed about 205 pounds, had a body mass index of 32 kg/m2, and an A1c of 7.0%.
They were randomly assigned to be in the low-carb breakfast group or the low-fat (control) breakfast group.
They were advised to choose one of the suggested breakfast recipes/menus for their group each day, and to follow the recipe exactly. They also had to upload a photograph of their breakfast every morning.
The patients did not receive any advice about foods or calories for the remaining meals.
They also filled in 3-day food records and answered a questionnaire about exercise, hunger, and fullness at the beginning, middle, and end of the intervention.
They also reported their height, weight, and waist circumference, and they had blood tests for A1c done at a local laboratory at the beginning, middle, and end of 12 weeks. The participants also wore a continuous glucose monitor during the first and last 14 days of the intervention.
At the end of the 12 weeks, the change in A1c was similar in both groups. Weight, BMI, and waist circumference decreased by a similar, very small, amount in each group as well. There were also no significant differences in hunger, fullness, or physical activity between the two groups.
But the 24-hour continuous glucose monitor data showed that average and maximum blood sugar levels, changes in blood sugar levels throughout the day, and time when blood sugar was higher than it should be (time above range) were all significantly lower in the people in the low-carbohydrate breakfast group than in the control group.
The time when blood sugar was what it should be (time in range) was also significantly higher among people in the low-carb breakfast group.
The average and the maximum blood sugar levels 2 hours after breakfast were lower for people in the low-carbohydrate breakfast group, the researchers found.
