Nutrient/Meal Timing: A Dozen Examples of Its Purported Impact on 'Ur Health, Weight Management & Body Comp.
Another factor that has been recognized to do just that is nutrient timing, i.e. the ingestion of food or specific foods and nutrients at specific, purportedly "optimal" time-points. In the fat-o-phobic 1980s, the mantra was: eat small quantities of low GI high carb foods every 2h. The result was a snacking culture that has probably contributed to the exponential rise of obesity rates over the past decade.
I've written about the problems that are associated w/ eating 24/7 in previous articles (e.g. "Many Small Meals Suck! Especially For Diabetics", "Are Six Meals Better Than Two?" or "Prevent Body Fat Gain by Eating Most of Your Calories Early in the Day") - just as I've addressed the potential benefits of the frequent ingestion of high protein meals as it is also suggested in the ISSN's position stand on nutrient timing (read it). With 2018 being only a few days away, I decided to use the holidays to take another look at the potentially relevant new evidence on meal/nutrient timing which is (and always has been) one of the five most frequent topics of e-mail and Facebook questions I get.
Next, to the previously referenced ISSN position stand, a cursory review of previous research overviews produces, among other results, the following insights:
- meal timing (MT) may inhibit the growth of cancer (vs. ad-libitum intake | Li 2010) - most likely by reinforcement of the host circadian timing system with MT induced 24-hour rhythmic expression of critical genes in clock-deficient tumors, which translated into cancer growth inhibition
- meal timing (MT) influences and, ideally, synchronizes the central and peripheral clocks of your body to ensure optimal endocrine, metabolic and immune function by making sure that corticosterone, ghrelin, leptin, insulin, glucagon, and glucagon-like peptide 1 are released/metabolized at optimal intervals
Table 1: Summary of human studies of eating frequency (Kaczmarek 2017b)
- the notion that "one size/timing fits them all" is flawed for having/skipping breakfast and meal frequency, in general - more specifically, previously discussed studies by Thomas et al. (read up on it) and LeCheminant et al. (read up on it) suggest that you better stick to what has been working for you in the past instead of forcing or depriving yourself of breakfast all of a sudden
- the observed benefits and detrimental effects of increased meal frequency, eating a large dinner, eating before bed, etc. have been shown to be mediated (at least partly) by their impact on people's total daily energy intakes -- in multivariate analyses controlling for age, sex, sleep duration, and timing, eating more frequently, later timing of the last meal, and a shorter duration between last meal and sleep onset predicted higher total caloric intake (Reid 2014); other confounding factors are results of the still prevalent advice not to skip breakfast or to eat breakfast like a king and dinner like a pauper or rather the fact that people who live a health-conscious life and eat healthy diets tend to adhere to this recommendation (Leech 2015).
Figure 2: During weight loss, consuming the most energy in the AM does not improve weight loss, insulin sensitivity and reduces hepatic fat content more than consuming the most energy in the PM (Versteeg 2017).
- while there is quite a number of studies, the study quality is generally low - with small sample sizes, short-term interventions, a lack of clear-cut definition of "an eating occasion" and a severe lack of several key outcomes such as physical activity, adherence to assigned EF, and hunger (Palmer 2009)
- the "carbohydrate-last"-principle which was posited by Shukla et al. (2017) based on the observation that a "carbohydrate-last meal pattern lowers postprandial glucose and insulin excursions in type 2 diabetes" (Shukla 2017) -- in fact, the scientists' data showed significant reductions in the incremental areas under the curve for glucose (iAUC0-180) and incremental glucose peaks of 53% and 54%, respectively, when carbohydrate was consumed last compared with carbohydrate consumed first and by 44% and 40%, respectively, compared with the all components together condition
Figure 4: Circadian Align- vs. Misalignment (Poggiogalle 2017).
As the overview in Figure 4 illustrates, controlled light exposure, healthy sleep habits and timed eating may help avoid or at least ameliorate health problems related to circadian misalignment.
- the fat difference between consuming almonds as a snack vs. preload that was observed only recently in healthy, young Korean adults between 20-39 - while all followed the same high-carb diets (isocaloric) all subjects were instructed to consume 56 g of almonds per day, one group did that as a preload before meals, while the other snacked between meals; with profound differences in health-relevant outcomes over the 16 week study period: "Almond consumption as a preload modified body fat percentages, whereas snacking on almonds between meals improved blood lipid profiles" (Liu 2017).
- further evidence that our tolerance to carbohydrates, even low GI carbohydrates, deteriorates from AM to PM (Leung 2017)- more specifically, when healthy test subjects consume a low GI meal (3.3 MJ, 48% energy (E) from carbohydrate, 40%E from fat and 11%E from protein, 22 g fiber) at 0800h, 2000h and 0000h (midnight), they will display higher postprandial glucose iAUC over 3h after the meal both, in the evening and at midnight (p = 0.008, p = 0.021 | no significant difference between evening and midnight (p = 0.594) was observed); similar observations were made for the postprandial insulin iAUC which was also higher in the evening and at midnight compared to the morning (p = 0.008 for both).
- evidence that our microbiome has its own biological clock comes from the University of Illinois at Urbana-Champaign (Kaczmarek 2017a) - if we are honest, we do, however, not really know if that's even relevant and what we could do with these new insights
- Beccuti, G. et al. "Timing of food intake: Sounding the alarm about metabolic impairments? A systematic review." Pharmacological research (2017).
- Dhurandhar, Emily J., et al. "The effectiveness of breakfast recommendations on weight loss: a randomized controlled trial." The American journal of clinical nutrition 100.2 (2014): 507-513.
- Li, Xiao-Mei, et al. "Cancer inhibition through circadian reprogramming of tumor transcriptome with meal timing." Cancer Research 70.8 (2010): 3351-3360.
- Mattson, Mark P., et al. "Meal frequency and timing in health and disease." Proceedings of the National Academy of Sciences 111.47 (2014): 16647-16653.
- Kaczmarek, Jennifer L., Salma MA Musaad, and Hannah D. Holscher. "Time of day and eating behaviors are associated with the composition and function of the human gastrointestinal microbiota." The American journal of clinical nutrition (2017a): ajcn156380.
- Kaczmarek, Jennifer L., Sharon V. Thompson, and Hannah D. Holscher. "Complex interactions of circadian rhythms, eating behaviors, and the gastrointestinal microbiota and their potential impact on health." Nutrition reviews 75.9 (2017b): 673-682.
- Leech, Rebecca M., et al. "Understanding meal patterns: definitions, methodology, and impact on nutrient intake and diet quality." Nutrition research reviews 28.1 (2015): 1-21.
- Leung, Gloria KW, Catherine E. Huggins, and Maxine P. Bonham. "Effect of meal timing on postprandial glucose responses to a low glycemic index meal: A crossover trial in healthy volunteers." Clinical Nutrition (2017).
- Liu, Yanan, et al. "The effects of daily intake timing of almond on the body composition and blood lipid profile of healthy adults." Nutrition research and practice 11.6 (2017): 479-486.
- Patton, Danica F., and Ralph E. Mistlberger. "Circadian adaptations to meal timing: neuroendocrine mechanisms." Frontiers in neuroscience 7 (2013).
- Patterson, Ruth E., et al. "Intermittent fasting and human metabolic health." Journal of the Academy of Nutrition and Dietetics 115.8 (2015): 1203.
- Poggiogalle, Eleonora, Humaira Jamshed, and Courtney M. Peterson. "Circadian Regulation of Glucose, Lipid, and Energy Metabolism in Humans." Metabolism (2017).
- Reid, Kathryn J., Kelly G. Baron, and Phyllis C. Zee. "Meal timing influences daily caloric intake in healthy adults." Nutrition Research 34.11 (2014): 930-935.
- Shukla, Alpana P., et al. "Carbohydrate-last meal pattern lowers postprandial glucose and insulin excursions in type 2 diabetes." BMJ Open Diabetes Research and Care 5.1 (2017): e000440.
- Thomas, E. A., Higgins, J., Bessesen, D. H., McNair, B. and Cornier, M.-A. (2015), Usual breakfast eating habits affect response to breakfast skipping in overweight women. Obesity. doi: 10.1002/oby.21049
- Vetter, Celine, and Frank AJL Scheer. "Circadian Biology: Uncoupling Human Body Clocks by Food Timing." Current Biology 27.13 (2017): R656-R658.