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By Hassan S Dashti, PhD

When we describe our habitual diets, we often find ourselves talking about its nutritional composition (i.e. what) and quantity (i.e. how much), however novel research suggests that timing of intake might be yet another important component of diet we want to pay attention to. This was the main focus of discussion at the ASN Scientific Sessions at EB 2015 symposium titled, “Is ‘When’ We Eat as Important as ‘What’ We Eat? – Chronobiological Aspects of Food Intake” (read more here: https://www.nutrition.org/asn-blog/2015/04/timing-is-everything/). Biologically, this makes sense as an endogenous clock, commonly termed the circadian clock, regulates a constellation of biologic processes, including metabolism (1). If up to 30 percent of genes in the intestines, liver, and kidney fluctuate throughout the day, yielding varying temporal functional profiles, doesn’t it make sense that there ought to be a time when dietary intake is optimal? Well, if the effect of a calorie on health is dependent on timing, what we all would like to know next is at what time should we be eating?

What currently determines our timing of intake is our culture and lifestyle for the most part. For instance, kids’ lunchtime is predetermined by school cafeterias, adults’ dinnertime is predetermined by rush-hour traffic, but even breakfast also seems to determine when we’ll have our next meal, lunch (2). History also played a role in determining meal times. In certain parts of the world, lunchtime was set for noon to enable workers to cope with long working hours in factories during the Industrial revolution. Perhaps it’s time to have science determine our meal hours.

Preliminary evidence suggests that earlier meal times tend to be healthier and “better aligned” with our biological clock. In one study, it was found that calories consumed after 8:00pm significantly predicted higher BMI (3). Meanwhile results from a 20-week weight loss intervention among overweight and obese individuals suggested that late eaters (lunch after 3:00pm) were less successful at weight loss compared to early eaters (lunch before 3:00pm), independent of 24-hour energy intake (4). Another trial assessing overweight and obese women further identified that high-calorie breakfasts, as opposed to high calorie dinners, were more beneficial for various cardiometabolic traits (5). Consistent with the findings from these trials is a cross-sectional analysis of a diverse cohort in the Los Angeles area that suggested that participants who consumed over a third of their calories by noon were less likely to be overweight and obese (6).

While these findings generally suggest that earlier hours of intake are generally healthier, they are not without their many limitations. One limitation worth noting is the high interrelatedness between timing of intake and other aspects of diet and life that also impact overall health and particularly sleep timing and duration, frequency of intake, and hours of fasting. Therefore, future studies should account for these strongly related dimensions when elucidating the timing of intake that best aligns with our internal clock.

1.Garaulet M, Gómez-Abellán P. Timing of food intake and obesity: a novel association. Physiol Behav. 2014 Jul;134:44–50.
2.Kant AK, Graubard BI. Within-person comparison of eating behaviors, time of eating, and dietary intake on days with and without breakfast: NHANES 2005-2010. Am J Clin Nutr. 2015 Sep;102(3):661–70.
3.Baron KG, Reid KJ, Kern AS, Zee PC. Role of sleep timing in caloric intake and BMI. Obesity (Silver Spring). 2011 Jul;19(7):1374–81.
4.Garaulet M, Gómez-Abellán P, Alburquerque-BÉjar JJ, Lee Y-C, Ordovás JM, Scheer FAJL. Timing of food intake predicts weight loss effectiveness. Int J Obes (Lond). 2013 Apr;37(4):604–11.
5.Jakubowicz D, Barnea M, Wainstein J, Froy O. High caloric intake at breakfast vs. dinner differentially influences weight loss of overweight and obese women. Obesity (Silver Spring). 2013 Dec;21(12):2504–12.
6.Wang JB, Patterson RE, Ang A, Emond JA, Shetty N, Arab L. Timing of energy intake during the day is associated with the risk of obesity in adults. J Hum Nutr Diet. 2014 Apr;27 Suppl 2:255–62.

By Brett Loman

Nutrition may be a relatively young science, but perhaps the intuition of our elders has informed us more than we realize. Food superstitions are as old as culture itself and essentially every civilization has added its share to the ever-growing list of dos and don’ts. In respect to two months in a row with Friday the 13ths this year, I investigated how some long-standing tales about what we eat might actually be grounded in truth.

Spilling salt brings bad luck. This widely recognized superstition originating in ancient Greece may hold some hidden truths. One of the most commonly believed concepts about sodium (salt) today is that eating too much can aggravate conditions such as hypertension, cardiovascular disease, and chronic kidney disease. The American Heart Association and National Kidney Foundation recommend limiting salt consumption to about 1,500 mg/d. So whether you believe the superstition or modern medicine, you will think twice and shake the habit of spilling salt onto your meal.

Eating garlic, onions, and mustard seeds is good luck by granting blessings or warding off evil. This superstition is rooted in many proverbs, and it just so happens that vegetables in the Amaryllis (onions, garlic, etc) and Brassicaceae (mustard, broccoli, etc) families are being investigated as anticarcinogens. Many of the naturally occurring phytochemicals in these plants may serve to halt the formation of cancer causing compounds, enhance repair of damaged DNA, and induce apoptosis of tumor cells. Chowing down on these luckily talismans could ward off disease, but don’t forget that those same beneficial compounds may also scare off your friends with the odors they leave lingering behind.

Bringing bananas on a boat will cause fishermen ill will and a bad catch. Green bananas, coincidentally, may just cause some unwanted symptoms of illness. Un-ripened bananas are a good source of resistant starch. Depending on your personal disposition, fermentation of resistant starch could either provide a healthy dose of short-chain fatty acids to the intestines, or a healthy dose of gas and diarrhea. Any angler would have difficulty landing the big one between frequent trips to the loo, and that’s no fish tale.

Planting parsley will help a woman become pregnant. Of course having good nutrition is important for increasing chances of beginning a pregnancy, but parsley is specifically of interest for the health of the newly developing fetus. This ubiquitous herb is a good source of many vitamins and minerals, including folic acid. In the first few weeks, adequate folate is especially important for preventing neural tube defects in the rapidly growing baby. Consider sowing seeds of parsley before sowing your wild oats.

Every day we find out more and more about how our eating habits affect our bodies, but in some cases we shouldn’t overlook what prior generations have already provided us. Tell the researchers and your grandma thanks for the advice.

References
1. Cobb, L.K., Anderson, C.A.M., Elliott, P., et al. Methodological issues in cohort studies that relate sodium intake to cardiovascular disease outcomes: A science advisory from the American Heart Association (2014) Circulation, 129 (10), pp. 1173-1186. http://www.scopus.com/inward/record.url?eid=2-s2.0-84895928005&partnerID=40&md5=75ecd90a4f86d73a8c200d300b4ca6c8
2. https://www.heart.org/HEARTORG/GettingHealthy/NutritionCenter/HealthyEating/About-Sodium-Salt_UCM_463416_Article.jsp
3. https://www.kidney.org/atoz/content/sodiumckd
4. http://www.cancer.gov/cancertopics/factsheet/prevention/garlic-and-cancer-prevention#r18
5. http://www.cancer.org/treatment/treatmentsandsideeffects/complementaryandalternativemedicine/dietandnutrition/broccoli
6. http://digestivehealthinstitute.org/2013/05/10/resistant-starch-friend-or-foe/
7. http://ndb.nal.usda.gov/ndb/foods/show/3080?fg=&man=&lfacet=&format=&count=&max=25&offset=&sort=&qlookup=parsley
8. http://www.cdc.gov/features/folicacidbenefits/