CHICAGO – Overweight patients with type 2 diabetes who ate only breakfast and lunch lost more weight than did those eating six meals a day in a randomized, crossover study.
They also had greater decreases in fasting plasma glucose, C-peptide, glucagon, and hepatic fat content, and bigger improvements in insulin sensitivity.
"Our data suggest that consuming a hearty breakfast and lunch may be more beneficial for patients with type 2 diabetes than eating more, smaller meals during the day," Dr. Hana Kahleová, said at the annual scientific sessions of the American Diabetes Association.
When asked whether eating a big lunch and dinner would produce the same benefits given the difficulty clinicians would face convincing patients to give up their evening meal, Dr. Kahleová agreed it would be a hard sell, but said the breakfast/lunch schedule is more beneficial. She highlighted research during the presentation showing fat deposition is greater following dinner (J. Clin. Endocrinol. Metab. 2009;94:1781-8), and that diabetes-free people of Mediterranean heritage who ate most of their daily intake early lost more weight and did so at a faster rate than did late eaters (Int. J. Obes. [Lond.] 2013;37:604-11).
"Our results support the ancient proverb: Eat breakfast like a king, lunch like a prince, and dinner like a pauper," said Dr. Kahleová of the Diabetes Centre, Institute for Clinical and Experimental Medicine, Prague.
Session moderator Dr. Anastassios Pittas, codirector of the Diabetes Center at Tufts Medical Center in Boston, said in an interview that few clinicians are in favor of six small meals a day because invariably patients will eat six moderate-size meals. Insulin dosing with such frequent meals is also more onerous.
"I agree with the finding that two is better than six, but that does not imply that, in general, the concept of fewer meals is better than more meals," he said. "It’s just that the comparison groups were so extreme that it’s logical to me what happened. I think the better, clinically applicable comparison would have been two vs. four or maybe five meals."
The six-meal diet was chosen as the comparator because it has been usually recommended that patients with type 2 diabetes eat five to six small meals during the day, Dr. Kahleová said in an interview. Although diabetic patients who eat small regular meals are reported to have better control of their blood glucose concentrations, the current results are strongly supported by animal studies showing the antidiabetic effects of caloric restriction and intermittent fasting diets. These effects include reduced blood glucose and insulin concentrations and improved glucose tolerance in rodents and are thought to be driven largely by increased insulin sensitivity.
Dr. Kahleová and her associates evenly randomized 54 patients with type 2 diabetes for more than 1 year to follow a six meals/day or two meals/day diet for 12 weeks. The diets were then switched for a subsequent 12 weeks. Both diets had the same caloric restriction (–500 kcal/day), carbohydrates (50%-55%), proteins (20%-25%), fats (25%-30%), cholesterol (less than 200 mg/day), and fiber (30g-40g/day).
For the two-meal diet, breakfast was eaten between hours 6-10 and lunch between hours 12-16. In the six-meal diet, breakfast was eaten during hours 6-8, snack hours 8-10, lunch hours 11-13, second snack hours 14-15, dinner hours 17-18 and second dinner hours 20-21.
To improve compliance, each regimen was started with a 4-day tutorial on how to compose and prepare their diet; group meetings with a dietician; individual counseling and meals provided for half of the patients. Patients were also asked not to alter their exercise habits during the study.
At baseline, 54% of patients were female, average diabetes duration 8.1 years, average body mass index 32.6 kg/m2, and average hemoglobin A1c 7.2%. Their average age was 59.4 years.
At 12 weeks, the mean change in BMI significantly favored the two-meal diet over the six-meal diet (–1.23 kg/m2 vs.–0.82 kg/m2; P less than .001), Dr. Kahleová said. Waist circumference shrunk significantly more as well (–5.14 cm vs. –1.37 cm; P less than .001).
Fasting plasma glucose decreased in response to both diets, but the decrease was significantly greater with two meals per day (–0.78 mmol/L vs. –0.47 mmol/L; P = .004), she said. C-peptide followed the same pattern (P = .04).
Hepatic fat content, as measured by proton magnetic resonance spectroscopy, decreased significantly more with two meals per day (–4.2% vs. –3.4%; P less than .001).
HbA1c decreased comparably in both diets, Dr. Kahleová said. Fasting plasma glucagon decreased with two daily meals (P less than .001), while it increased with six meals (P = .04).