Research Review Shorts: Do Irregular Meal Times Impact Calorie Expenditure?
Years ago it was thought that consuming many small meals throughout the day would help increase the rate of energy expenditure. While this myth has since been debunked, a recent paper looked at whether or not consistent meal times was more favorable for increasing total energy expenditure than irregular meal times.
Some coaches and individuals use simple, relatively loose guidelines in their process of dieting. Set a calorie target and hit your macros consistently – that’s it.
Others use a more complex approach, focusing on variables such as meal timing, food source selection, pre and post workout nutrition, etc.
In the latter approach, a considerable amount of attention is placed on smaller nutritional details, details that may not be all that relevant to the individual’s goals.
This is something I see ALL the time; coaches assigning their clients with grueling constraints, and when the clients finds themselves being unable to follow the constraints they feel like they’ve failed.
The study we’re looking at today, examines one of these “smaller” nutritional details – meal patterns and consistency.
This was a crossover study, in which 9 free-living women with insulin resistance underwent two separate 14-day experimental conditions in randomized order.
Condition 1: Regular meal schedule consisting of six meals per day.
Condition 2: Irregular meal schedule averaging six meals per day, but varied from three to nine meals on any particular day.
Meals were provided during both experimental phases, and participants were instructed to maintain their typical physical activity habits.
- The thermic effect of feeding was significantly higher (by about 20.9kJ) after the regular meal pattern than after the irregular meal pattern.
- Significantly larger GLP-1 responses to a standardized test drink were observed following the regular meal pattern in comparison to the irregular meal pattern. *GLP-1 is a peptide hormone associated with subjective appetite suppression and reduced energy intake, so higher GLP-1 levels are considered to be favorable with regards to satiety regulation.
Interpretation & Takeaways
Given these two findings, many would interpret that regular meal patterns lead to a higher total daily energy expenditure and GLP-1 levels. Thus you could conclude that regular meal patterns lead to more calories burned and less hunger throughout the day.
If we take these energy expenditure values to be perfectly valid and reliable representations of the full thermic effect of feeding, it’s hard to get excited about the fact that the regular meal pattern led to a 20.9kJ (or ~5kcal) higher thermic effect of feeding value.
If we don’t take these energy expenditure values to be perfectly valid and reliable representations of the full thermic effect of feeding, then an alternative interpretation is that there’s a little bit of “noise” in the data (which is perfectly understandable) and an incomplete observation window, which also makes it hard to get too excited about a 20.9kJ increase.
Either way, I think it’s really hard to claim that these differences in the thermic effect of feeding are going to have a physiologically meaningful impact on total daily energy expenditure, especially when the study does not provide comprehensive measurements of the other components of energy expenditure.