People with Type 2 diabetes are often advised to eat a calorie-controlled diet broken down into five or six small meals over the course of the day. But now a small new study from researchers in the Czech Republic suggests that eating those calories in two large meals each day may be better for controlling blood glucose levels and weight. Roughly 600,000 people in the Czech Republic and 25 million people in the United States have Type 2 diabetes.
Studies in animals have indicated that reducing the frequency of meals may extend lifespan and reduce the risk of chronic diseases, and observational trials in humans have suggested that eating more than three times a day may play a role in overweight and obesity. To clarify the relationship between eating frequency and glucose control and weight in people with Type 2 diabetes, researchers recruited 54 people (29 men and 25 women) to test the effects of two dietary regimens. The participants were all between 30 and 70 years old, overweight or obese, and being treated with oral diabetes medicines; their A1C levels (a measure of glucose control over the previous 2–3 months) ranged from 6% to 11.8%.
The study subjects were randomly assigned to one of two meal plans, one consisting of six small meals a day and the other consisting of two large meals (breakfast and lunch) a day. Both diets had the same nutrient and calorie content (on average, about 1700 calories a day — roughly 500 calories less than the daily recommended amount). All of the participants followed their assigned diet for 12 weeks, then switched to the alternate diet. Various health markers, including liver fat content, beta-cell function (the function of the insulin-producing cells of the pancreas), and insulin sensitivity, were measured during the course of the study.
At the conclusion of the study period, the researchers found that weight, liver fat content, fasting plasma glucose, and C-peptide levels (an indicator of insulin production) had decreased in both groups, but to a greater extent in those following the two-meal regimen. Additionally, levels of fasting plasma glucagon (a hormone that promotes glucose secretion by the liver) had fallen in those eating two meals a day but increased in those eating six meals a day.
“Mostly it has been recommended for people with Type 2 diabetes to eat five or six small meals a day, but in Western societies at least, it turns out that snacks are not healthy, they are high in sugar and fat. So a regimen of frequent eating hasn’t resulted in better control,” noted lead study author Hana Kahleová, MD.
In an interview with Medscape Medical News, the researchers suggested that the practical takeaway of the findings is that “three meals a day is enough; breakfast should be the largest meal of the day, and dinner may be light.”
“The old saying, ‘Eat breakfast like a king, lunch like a prince, and [dinner] like a pauper’ may indeed hold true,” observed Kahleová.
Because the trial involved only 54 people, larger, longer-term studies are needed to confirm the findings, the researchers note.
For more information, read the article “Breakfast Like a King: 2 Large Meals Benefit Diabetes” or see the study in the journal Diabetologia. And to learn more about maintaining blood glucose control, read “Managing Your Blood Glucose Ups and Downs” by pharmacist Stacy Griffin and certified diabetes educator Diane Ballard.