The Right Foods at the Right Time: Circadian Rhythms and Nutrition

Part of National Nutrition Month’s theme of “Put Your Best Fork Forward” is not only choosing the right foods, but also at the right time. The circadian rhythm, or a person’s 24-hour cycle, is a relatively new piece of the puzzle to understanding the obstacles we face to achieve a healthy lifestyle. Though ongoing, there has been some research looking deeper into the relationship between mealtime and its physiological effects. Delayed sleep-wake cycles have been linked to increased body mass index, which in turn can have detrimental effects on sleep. Delay in following one’s usual circadian rhythm has been associated with increased calorie consumption from snack foods and sugar-sweetened beverages, possibly because of increased waking time.

One study took a closer look at the intersection of the circadian system, the behavioral cycle: including the sleep/wake and fasting/feeding cycles: and the impact of these patterns on glucose tolerance levels. In this study, some participants were monitored during “normal” days in which they ate meals at the same times, while others were studied during flipped sleep and meal schedules: breakfast was eaten at night, dinner in the morning, and there was wakefulness through the night. In the end, those whose circadian rhythms were altered resulted in an increased risk of Type 2 diabetes. There are two theories as to the cause of the glucose tolerance changes: one, a reduction in the function of beta cells, which are responsible for producing insulin to manage blood sugar levels, and two, a possible decrease in insulin sensitivity.

The misalignment of our internal clock is perceived to be due to light exposure. Light works as a main cue to reset the brain clock. When our meal times do not match our sleep-wake cycles, there is a disconnect in this otherwise natural process.  This has crucial implications for those who alter their circadian rhythms in some way. Shift workers, who work outside of a typical 9-to-5 schedule (usually at night), are at increased risk for certain ailments, including Type 2 diabetes. For those who are nighttime snack food grazers, weight gain may be more likely to occur when someone consumes foods rich in carbohydrates closer to bedtime.

The best way to promote a healthy circadian rhythm is to try to get the right amount of sleep and eat regular meals at times that are relatively distributed throughout the day. And, most importantly, be consistent. Though difficult, consistency is the best way to create and set a circadian rhythm that benefits you and helps to reduce your risk of developing nutrition-related conditions.

The exciting news is that unlike our genetics that can predispose us to certain chronic illnesses, we can choose what we eat and when we eat it. These choices allow us to play a role in prevention of illness and management of our health.

Zach Breeding, MS, RDN, LDN, FAND, is a Philadelphia-based registered dietitian nutritionist, professional chef and clinical dietitian of the Cystic Fibrosis Clinic at Drexel University College of Medicine. He is the author of The Slice Plan: An Integrative Approach to a Healthy Lifestyle and a Better You. Connect with Zach on his website, The-Sage: Nutritious Solutions, and on Facebook and Twitter.