The new study compared the effect of different dietary patterns on measures of blood glucose, dietary lipids and hormone levels in people with type 2 diabetes.
Led by researchers at Linköping University in Sweden, the three diets assessed were a low-fat diet, a low-carbohydrate diet and a Mediterranean diet.
"We found that the low-carbohydrate diet increased blood glucose levels much less than the low-fat diet but that levels of triglycerides tended to be high compared to the low-fat diet," said Dr Hans Guldbrand, who together with Professor Fredrik Nystrom was the principal investigator of the study.
"It is very interesting that the Mediterranean diet, without breakfast and with a massive lunch with wine, did not induce higher blood glucose levels than the low-fat diet lunch, despite such a large single meal," Nyström revealed. "This suggests that it is favourable to have a large meal instead of several smaller meals when you have diabetes, and it is surprising how often one today refers to the usefulness of the so-called Mediterranean diet but forgets that it also traditionally meant the absence of a breakfast."
"Our results give reason to reconsider both nutritional composition and meal arrangements for patients with diabetes," he added.
Writing in PLoS One, the research team assessed the impact of the three diets in 21 volunteers who received each test diet in a randomly assigned order. The low-fat diet had a nutrient composition that has traditionally been recommended in the Nordic countries, with about 55% of the total energy from carbohydrates. The low-carbohydrate diet had a relatively low content of carbohydrate; approximately 20% of the energy was from carbohydrates and about 50% of the total energy came from fat. The Mediterranean diet was composed of only a cup of black coffee for breakfast, and with all the caloric content corresponding to breakfast and lunch during the other two test days accumulated to one large lunch.
During each test day blood samples were collected at six time points.
"The large Mediterranean-style lunch-meal induced similar postprandial glucose-elevations as the low-fat meal despite almost double amount of calories due to a pronounced insulin-increase," explained the team. "This suggests that accumulation of caloric intake from breakfast and lunch to a single large Mediterranean style lunch-meal in NIDDM might be advantageous from a metabolic perspective."
Source: PloS One
Published online ahead of print, doi: 10.1371/journal.pone.0079324
"A Randomized Cross-Over Trial of the Postprandial Effects of Three Different Diets in Patients with Type 2 Diabetes"
Authors: Hanna Fernemark, Christine Jaredsson, et al