The notion [of high meal frequency] has been put into question by the recognition of a high level of dietary underreporting in overweight individuals. In addition, no difference in total daily energy expenditure has been documented as a function of daily meal number. Weight loss is not facilitated by high meal frequency. Snacking in obese subjects is associated with higher energy and fat intake.”

By contrast, in normal-weight people, snacking does not necessarily lead to increased energy intake, while snacks often contain more carbohydrates and less fat than regular meals.

Verdict of the Study 

This study suggests that there are no documented studies of increased daily enery expenditure by increasing meal frequency. 

 “When [equal amounts of calories] was given as two meals per day or six meals per day there was found to be no significant difference in total energy expenditure.”

This data suggest that when the nutrient load was spread into equal amounts and consumed evenly through the day in lean healthy males, there was an enhanced control of appetite. This greater control of satiety when consuming smaller multiple meals may possibly be linked to an attenuation in insulin response although clearly both other physical (gastric stretch) and physiological (release of gastric hormones) factors may also be affected by the periodicity of eating.

As compared with the three-meal diet, the nibbling diet reduced fasting serum concentrations of total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein B by a mean (±SE) of 8.5±2.5 percent (P<0.02), 13.5±3.4 percent (P<0.01), and 15.1±5.7 percent (P<0.05), respectively. Although the mean blood glucose level and serum concentrations of free fatty acids, 3-hydroxybutyrate, and triglyceride were similar during both diets, during the nibbling diet the mean serum insulin level decreased by 27.9±6.3 percent (P<0.01) and the mean 24-hour urinary C-peptide output decreased by 20.2 ±5.6 percent (P<0.02). In addition, the mean 24-hour urinary cortisol excretion was lower by 17.3±5.9 percent (P<0.05) at the end of the nibbling diet than at the end of the three-meal diet. The blood glucose, serum insulin, and C-peptide responses to a standardized breakfast and the results of an intravenous glucose-tolerance test conducted at the end of each diet were similar. 

We conclude that in addition to the amount and type of food eaten, the frequency of meals may be an important determinant of fasting serum lipid levels, possibly in relation to changes in insulin secretion. (N Engl J Med 1989; 321:929–34.)

Verdict of the Study 

While the number of pariticipants was low; it did examine the effects of multiple meals versus bigger meals less often. The most important point to take away from this study was that both levels of serum insulin and urinary cortisol were lower in the multiple meal group. If you are unsure what this means, it's ok, keep reading.

General recommendations? 
Example: 200 lb male athlete/bodybuilder 5 meals per day (one meal every 4-6 hours) 
Goal: 4g/leu per meal (0.045g leu/kg BW/meal) 
Meal protein sources: 
2 meals: whey (33g protein at each meal)
2 meals: chicken (54g protein at each meal) 
1 meal: beef (51g protein) Total protein intake: 225g/day 3-4g leu supplement consumed between meals may optimize MPS response.

Observations from the latter
study and the present study indicate that a low meal frequency
could be detrimental because it may reduce fat oxidation, due
to the postponed fat oxidation after a high carbohydrate load,
and promote fat storage due to the lower ability to compensate
for fat intake.

In healthy, normal-weight women, decreasing the inter-meal
interval sustains satiety, particularly over the day, and sustains
fat oxidation, particularly over night. Increasing meal fre-
quency, and thereby decreasing inter-meal frequency, in a
state of energy balance may be a useful tool to prevent large
fluctuations in feelings of satiety and substrate utilisation