A New Study Suggests 2 Meals/Day Is Best for Weight-loss in Diabetics: Let's Have a Look-See

The question of "what is the optimal meal frequency for weight-loss?" seems to never go away. Most of the evidence regarding the specific effects of high vs low meal frequency is inconclusive. Therefore when I came across the below study that seemed to indicate that meal frequency might very well play a critical role in helping people lose fat, I was understandably skeptical. Thus far, all we can really say with any amount of tentative certainty is that (1) neither a high nor low meal frequency effect diet induced thermogenesis, total energy expenditure, or resting metabolic rate, and (2) neither a high nor low meal frequency yield favorable changes in body composition in sedentary populations [1]. In regards to meal timing, some evidence suggest that being consistent/regular about when you eat--independent of meal frequency--may improve fasting lipid and postprandial insulin profiles and may have beneficial effects on thermogenesis [2]. Being haphazard about your meal timing, however, can have not-so-pretty effects, resulting in lower postprandial energy expenditure thus leading to increased fat mass, independent of increased calorie consumption [3].

Study: Eating two larger 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 randomised crossover study [4]

At first glance, this study seems promising. It has the makings of a truly influential bit of research. Upon further inspection, however, the actual data collected by the authors rather underwhelmed me. But before I go all pessimistic on you, let's break down what the researchers/authors of this study did.

Study Design

The authors used a "randomized cross-over study design." Participants were randomly assigned, via a computer algorithm, to 1 of 2 groups: One group consumed six meals/day (A6) (breakfast, lunch, diner, and 3 snacks) while the other group ate two (B2) (breakfast and lunch). Half way through the trial, the meal frequencies of the groups were switched. 54 people (all diabetic with BMIs between 27-50; ages ranged form 30-70) participated in the study. Seven of these participants dropped out before the study concluded--nevertheless, the results of these seven were included in the authors' analysis. The trial lasted 12 weeks.

Diet Composition

Each person participating in the study was fed a controlled diet wherewith all participants would be in a daily caloric deficit of about 500 calories. 50-55% of the participants' calories came from carbohydrate, 20-25% came from protein, and 30% came from fat. Half of all participants were picked at random to have their food pre-prepared for the duration of the trial. The other half had to prepare their own meals, keeping these meals consistent with the dietary guidelines set by the researchers.

Results

The authors' data showed that both the A6 and B2 regimens resulted in weight-loss; though the B2 regimen resulted in a greater amount (-3.7 kg for B2 vs 2.3 kg for A6). B2 also resulted in a greater loss of hepatic fat content (liver fat) (-.04% vs -.03%). Fasting plasma glucose and C-peptide levels decreased more with B2 (fasting plasma glucose actually increased with A6--not a good sign). Both groups saw an improvement in oral glucose insulin sensitivity; though, guess what?: B2 yielded a better improvement.

Considerations

Critique of Diet

• The participants of this study were diabetics. It therefore makes no sense to me why the researchers assigned them to a diet wherein 50-55% of their calories were derived from carbohydrate! The fact that this diet was carb-rich may have influenced the data. A high carb, six meals/day regimen is not inherently a diabetics best friend. 
• Diabetes results in impaired carbohydrate metabolism, and exposing those with this condition to frequent feedings of carbohydrate would obviously yield not-so-superior results. It makes sense, then, why the two meals/day regimen yielded marginally better results than the six meals/day regimen. Yes, those eating two meals/day had higher levels of carbohydrate to contend with when they did eat, but they also had less frequent feedings of carbohydrate overall. In my book, chronic stressors will more often cause problems than will acute stressors.
• While half of the subjects had their meals pre-prepared, the other half were responsible for their own meals. It is therefore hard to say whether or not this half adhered faithfully to the diet parameters.
• I would like to see what would happen if this study was conducted again; though with a lower carbohydrate protocol.

Critique of the Results

• Aside from the fact that the six meals/day regimen resulted in slightly worsened fasting insulin, both regimens resulted in weight loss, decreased hepatic fat content, and increased oral glucose insulin sensitivity. 
• Calories matter--even for diabetics--however, I think those with diabetes, because of their damaged metabolic condition, ought to pay close attention to the frequency and timing of carbohydrate consumption.
• Once again, the macrocomposition of the diet may have influenced the results of this study.
• The authors more rightly might have concluded that, in the context of a high carbohydrate hypocaloric diet, diabetics can better handle two large (and less frequent) carbohydrate feedings/day than they can handle six smaller (and more frequent) carbohydrate feedings/day.

Conclusion

The results from this study certainly are intriguing, however these results may reflect something entirely different from what the authors conclude. Meal frequency per se may not be the real factor that diabetics ought to take into the most consideration. Rather, the frequency of insulin spikes may be the more pertinent issue that those with diabetes need to consider. I'm merely speculating, but I think this is an hypothesis worthy of future investigation.