Dietary Strategies for T2DM: Are Two Meals Better Than Six?

Eating 2 meals a day may be better than eating 6 for glycemic control among people with type 2 diabetes mellitus (T2DM), according to a new study by researchers at Prague’s Charles University (Czech Republic), and recently published in Diabetologia.¹

“The main strength of our study is that it was a free-living study and we found out that the regimen of 2 meals a day is sustainable even for patients with diabetes,” commented first author Hana Kahleova, MD, PhD, of the Diabetes Center at the Institute for Clinical and Experimental Medicine in Prague (Czech Republic). “Our data strongly support the benefits of intermittent fasting in humans, although it is in contrast to the traditional standpoint that more frequent, smaller meals during the day are healthier.” 

Kahleova cautioned that the study’s short duration precludes definitive conclusions, and that larger, longer-term studies will be needed before anyone can provide firm recommendations about meal frequency among patients with T2DM.

Conventional wisdom holds that eating more frequent meals while on a low-energy diet helps curb hunger and decrease energy intake, but scientific studies have yet to prove that the strategy benefits health and longevity. On the contrary, studies in humans have begun to suggest that eating fewer, larger meals may be better for glycemic control in T2DM. Some studies point to certain harms associated with frequent eating, with more than 3 meals a day linked to overweight and obesity,² and frequent snacking linked to increased risk for T2DM.^3,4 In people with T2DM, one study suggested that eating a single large Mediterranean-style meal at lunch is better for glycemic control than eating 2 smaller meals.⁵ Other studies have linked eating larger meals later in the day with lower success of weight loss diets⁶ and increased fat storage after the evening meal.⁷

Key points of the study

• 24-week, single-center, randomized, crossover design

• 54 patients with T2DM on oral medication; mean age, 60 years; mean T2DM duration, 8.1 years; mean BMI, 32.6 kg; mean HbA1c, 7.2.

• Randomized to 1 of 2 low calorie diets (≈ 2000 kJ/d) for 12 weeks; then switched to the other diet for 12 weeks. 

• Dietary group B2: 2 meals per day-breakfast and lunch

• Dietary group A6: 6 smaller meals per day-breakfast, lunch, dinner, with 3 small snacks in between

• Existing medications maintained, with dose reductions for hypoglycemia

Key results

• Weight loss: B2 group lost more than A6 group (-3.7 kg vs -2.3 kg, respectively)   

• Hepatic fat content (HFC): B2 group saw greater reduction than A6 group (-0.03% vs -0.04%, respectively; P = .009). 

• Fasting plasma glucagon: Decreased in the B2 group (P < .001), but increased in the A6 group (P = .04). 

• HbA1c: Decreased about the same amount in both groups (-0.23% in A6 vs -0.29% in B2). 

The decrease in HFC was strongly associated with a decrease in fasting plasma glucose (P < .001), which remained significant after controlling for changes in BMI (P = .05).

The reduction in HFC among those on the 2-meal diet, the authors point out, may be one of the most important findings of their study: HFC is linked to insulin resistance, metabolic syndrome, T2DM, and subclinical atherosclerosis, while decreased HFC may increase insulin sensitivity. They also note the decreased glucagon levels among those on the 2-meal diet and highlight the similar therapeutic effect of the incretin-based agents.

Other possible mechanisms by which the 2-meal diet could provide benefits, according to the authors, include effects on circadian rhythms and on the satiety hormones leptin and ghrelin, as well as improved control of hunger and cravings.

“The take-home message from our study is that we need to concentrate on eating a large breakfast and dinner should be light. Eat breakfast like a king, lunch like a prince and dinner like a pauper,” emphasized Kahleova. She also added a proviso:  “Caution must be taken, especially by patients treated with insulin. All patients need to consult their physician and work with him.”

References:

• Kahleova H, Belinova L, Malinska H, et al. Eating two meals a day (breakfast and lunch) is more effective than six smaller meals in a  reduced-energy regimen for patients with type 2 diabetes: a randomized crossover study.  Diabetologia. doi:10.1007/s00125-014-3253-5.
• Howarth NC, Huang TT, Roberts SB, et al. Eating patterns and dietary composition in relation to BMI in younger and older adults. Int J Obes (Lond). 2007;31:675-684.
• Mekary RA, Giovannucci E, Willett WC, et al. Eating patterns and type 2 diabetes risk in men: breakfast omission, eating frequency, and snacking. Am J Clin Nutr. 2012;95:1182-1189. doi:10.3945/ajcn.111.028209.
• Mekary RA, Giovannucci E, Cahill L, et al. Eating patterns and type 2 diabetes risk in older women: breakfast consumption and eating frequency. Am J Clin Nutr. 2013;98:436-443. doi:10.3945/ajcn.112.057521.
• Fernemark H, Jaredsson C, Bunjaku B, et al. A randomized cross-over trial of the postprandial effects of three different diets in patients with type 2 diabetes. PLoS One. 2013;8:e79324. doi:10.1371/journal.pone.0079324.
• Garaulet M, Gómez-Abellán P, Alburquerque-Béjar JJ, et al. Timing of food intake predicts weight loss effectiveness. Int J Obes (Lond). 2013;37:604-611. doi:10.1038/ijo.2012.229.
• Ruge T, Hodson L, Cheeseman J, et al. Fasted to fed trafficking of fatty acids in human adipose tissue reveals a novel regulatory step for enhanced fat storage. J Clin Endocrinol Metab. 2009;94:1781-1788. doi:10.1210/jc.2008-2090.