Meal Frequency & Fat Loss

You have likely heard it before, but some people claim to eat several small meals a day to “stoke” the metabolism while others stick to a single or two meals a day to maximize fat loss while in their fasting window. In this article, we will examine the research on how meal frequency impacts fat loss, if more or less is better, and the physiological reasons for this scientific conclusion.

Meal Frequency & Fat Loss?

Much like most other scientifically investigated issues, this is no exception in that it requires some understanding of the conditions. In this case, we need to have both conditions be equal in calories, at the least, and preferentially, in macronutrient consumption, as well; this ensures that results are not due to bad experimental methodology. Luckily, there are several studies that have investigated meal frequencies between just 1 or 2 a day (“gorging”) compared to as much as 9 or more meals a day (“snacking”) with the conditions being equal in caloric content as necessary [1][3].

Of these studies, most, if not all, studies have shown that meal frequency makes no difference when it relates to fat loss [1][2][3][4]. This statement is barring some of the minute complexities of the issue (protein synthesis, ghrelin, satiety, etc.), which are not discussed in this article due to the fact that they likely make no real world physiological difference and can get overly complex for a general article such as this one.

Physiological reasoning?

If you read the Fasted Cardio & Fat Loss article, then you have a good idea of why these results are generally unsurprising.

When it comes to comparing groups, as we’ve stated earlier, there are several requirements; we need calories to be relatively equal, we need calories to be set in a deficit, and we need a variety of frequencies of consumption to compare. We need calories to be in an equal deficit, because we need to ensure weight loss and the only way to do that is by being in a calorie deficit. Once we have an established calorie deficit, say 500 calorie deficit, for every person compared, then we can go ahead and begin to understand how the physiology works.

In one corner, we have Frank, and Frank eats 5-6 meals a day, in a 500 calorie deficit. In the other corner, we have Sal, and Sal eats 1-2 meals a day, in a 500 calorie deficit. Frank has a higher frequency of consumption, but due to this, he must consume less per meal than Sal, because their calories are matched so as to create a 500 calorie deficit (assuming they consume the same calories to maintain their weight).

Now, to the physiology; we know that insulin is a hormone that allows blood glucose (blood sugar) to enter the cells to nourish them. We also know that blood glucose levels need to remain within a range of concentration, otherwise we die, because with no glucose in circulation, the cells are not fed, and if the cells are not fed, they die, and since the cells make up our body - we die.  Now, if a person consumes food, it is absorbed and insulin is released to shuttle the excess blood glucose into the cells; in simplistic terms, if this occurs too much, the body begins storing energy into the fat cells. However, both Frank and Sal are in a calorie (energy) deficit, so it is impossible for them to store the energy as fat, because they do not even have enough energy to maintain their current weight – hence the loss of fat.

That said, Frank eats one of his small meals and, predictably, insulin rises to shuttle blood glucose (energy) into the cell. Sal, however, does not eat breakfast, so his insulin does not rise (it stays at baseline), but again, the cells still need to be fed, so the body increases the release of fat stores from the fat cells to supply an “alternative” energy for the body cells – this process is called lipolysis [5]. So, at the beginning of the day, Sal is losing more fat than Frank, because Sal’s body increases lipolysis due to its lack of energy intake through food.

Then, by midafternoon, Frank has consumed his third of five meals and Sal has yet to eat a single meal – again, Sal is losing more body fat due to his fat cells dumping fat to feed the rest of the body and spare his blood glucose levels from dipping dangerously. However, by late afternoon, Frank finishes his last small meal and again his body has a small surge in insulin due to the intake of energy through food. At this time, Sal breaks his fast by consuming half of his total calories for the day in his first meal of the day. At this point, although Sal has been using stored fat the entire time to feed his body, his insulin skyrockets far higher than any of Frank’s meals, because Sal’s single meal makes up 2.5 of Frank’s little meals; it is at this point that Frank is now in a greater lipolysis state than Sal as Sal’s insulin increase is a result of his blood glucose increase leading to his body needing to shuttle all that excess glucose into the cells.

That said, however, Sal still has the benefit of having used his body fat for energy the entire day, so all in all, he has lost more body fat than Frank. Now, however, to equate calories, Sal must consume his last meal which contains the other half of his calories and Frank cannot consume anymore calories, so Frank’s insulin is back to baseline and his body is using fat to give his cells energy for the end of his day and sleep. Sal, after consuming his last meal (worth the other 2.5 meals of Frank’s consumption), has his insulin skyrocket again and it takes a while longer for his insulin to return to baseline as this massive influx of energy needs to be dealt with and shuttled into the cells. Again, during this time, Sal is not going through much, if any, lipolysis, but Frank is in full lipolysis mode.

Pictured, above, is a diagram of insulin release as a meal is ingested and blood glucose rises, as a result. One group was fasted, as seen with the relatively straight line with the diamond data points. Another group ate two large meals, as seen in the triangle data points, and showed two large insulin spikes. Finally, the third group, as seen in the square data points, ate numerous meals and although insulin rose, it also stayed consistent.

Diagram from [7]. 

Similarly, this diagram shows a similar study explaining the variance between groups in insulin response. The Low Frequency group had more dramatic increases and dips in insulin while the High Frequency group had more sustained insulin levels; however, both groups used relatively the same amount of insulin in total. 

Diagram from [6].

So, at the end of the day, although Sal had a head start throughout the day, the calories consumed are the same (relative to their bodies), so the body must respond in an equal measure by secreting the same amount of insulin in Frank and Sal’s case although the intensity of secretion was dissimilar and the frequency of stimulation was dissimilar; the total remains the same. As you can see, the body adjusts to the amount and frequency of consumption in a way that the total, at the end of the day, is the most important factor to look into. Are there other factors to consider? Absolutely, but in terms of weight loss (likely from mostly fat), the total after 24 hours is more important than the way it was reached.

Frank has more controlled “pulses” of energy intake, so his blood glucose levels are more stable and his insulin levels rise at a fraction of Sal’s [6][7]. Sal has more extreme rises in energy intake, so his blood glucose levels are a bit less stable and his insulin increases are noticeably higher and longer than Frank’s [6].

SUMMARY

All in all, meal frequency, if we strictly examine fat loss amount, has no impact on fat loss. Beyond the studies that express this conclusion, the physiological understanding would also lead to this same conclusion; total insulin is similar in both instances although the expression of insulin is different, but as total insulin is more telling of total fat loss, this is the measure we should focus on. Again, at points of the day, fat loss may be greater in one individual over another, but in a 24 hour period with equal calories and, hopefully macronutrient intake, it is shown that fat loss is the same.

Writer: Nicolas Verhoeven
This is educational material only and not meant to be prescripton, consult your physician before making any changes.

                                                                                                       Citations

[1] Bellisle, F., McDevitt, R., & Prentice, A. M. (1997). Meal frequency and energy balance. British Journal of Nutrition, 77(S1), S57. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/9155494

[2] Cameron, J. D., Cyr, M., & Doucet, É. (2009). Increased meal frequency does not promote greater weight loss in subjects who were prescribed an 8-week equi-energetic energy-restricted diet. British Journal of Nutrition, 1. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/19943985

[3] Klein, D. (n.d.). Meal Frequency and Weight Lossâ��Is There Such a Thing as Stoking the Metabolic Fire? Retrieved from https://www.nsca.com/education/articles/ptq/meal_frequency_and_weight_loss/

[4] Jon Schoenfeld, B., Albert Aragon, A., & Krieger, J. W. (2015). Effects of meal frequency on weight loss and body composition: a meta-analysis. Nutrition Reviews, 73(2), 69-82. Retrieved from http://www.alanaragonblog.com/wp-content/uploads/2015/01/2015-Schoenfeld-Aragon-Krieger-meal-frequency-meta-analysis.pdf

[5] Lass, A., Zimmermann, R., Oberer, M., & Zechner, R. (2011). Lipolysis – A highly regulated multi-enzyme complex mediates the catabolism of cellular fat stores. Progress in Lipid Research, 50(1), 14-27. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3031774/

[6] Munsters, M. J., & Saris, W. H. (2012). Effects of Meal Frequency on Metabolic Profiles and Substrate Partitioning in Lean Healthy Males. PLoS ONE, 7(6), e38632. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3374835/

[7] Solomon, T. P., Chambers, E. S., Jeukendrup, A. E., Toogood, A. A., & Blannin, A. K. (2008). The effect of feeding frequency on insulin and ghrelin responses in human subjects.BJN, 100(04). Retrieved from http://journals.cambridge.org/download.php?file=%2FBJN%2FBJN100_04%2FS000711450896757Xa.pdf&code=22c8f50b52c72a2e00062d1042e9273c

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