You may of heard of circadian rhythms, which prime our body for smoothly functioning sleep-wake cycles. While these primary cycles are run by a ‘master’ central circadian clock, we also have metabolic rhythms, which impact a whole lot of physical functions-food intake, fat accumulation, calorie expenditure, blood glucose values, hormone secretion, and digestive function. The times that we eat help to set phases of peripheral circadian clocks, while the content of meals also matters.
For instance, the circadian clock in our liver requires a combination of carbohydrate and protein to be reset. We can think of eating patterns as responsible for resetting our clock hands, while irregularly timed food intake can create some confusion for your metabolism. ‘Food entrainment’ is the internal mechanism whereby the phase and period of circadian clock genes comes under the control of daily scheduled food availability. Food entrainment allows the body to efficiently realign the internal timing of behavioral and physiological functions such that they anticipate food intake. Because of these metabolic impacts, when we eat may be as important as what we eat.
Although we so often talk about calories in and calories out as the master regulator of weight, reality is just not so straightforward.
Recent nutritional studies linked to chronobiology called “chrono-nutrition” have revealed a molecular associa-tion between energy homeostasis and the timing of meals. Skipping breakfast, eating late at night, ands hifted mealtimes can all induce obesity even without an increase in caloric intake For instance, although high fat diets eaten ad libitum have been seen to induce obesity and increase risk for metabolic diseases, time restricted feeding with a high-fat diet without caloric restriction suppresses obesity and metabolic diseases. Time restricted feeding is generally considered a daily eating pattern in which all nutrient intake occurs within a set number of hours, usually <12 hours every day (for instance, the first meal at 7:30am with the last meal at 6:30pm).
When we think about our naturally occurring metabolic clock, body temperature-and associated caloric burn-is higher in the morning, One study of two groups eating the same number of calories found more body weight loss, improvements in fasting glucose and insulin, improvements in triglycerides, and higher satiety (feeling satisfied with the amount of food eaten) scores in the group given a bigger breakfast and a smaller dinner than vice versa. These and other findings indicate that late meals and skipping breakfast leads to body weight gain and obesity in humans as well as in experimental animals. While eating sufficient amounts to fuel physical and mental ability throughout the day, the old adage to eat ‘breakfast like a king, lunch like a prince, and dinner like a pauper’ may promote healthier metabolic function and more smoothly regulated hunger and fullness signals.
Smaller, more frequent meals make sense for some who have gastrointestinal-related symptoms (including vomiting, bloating, and fullness), and could help to better regulate blood pressure and blood sugar in some individuals. When they are used in place of regularly scheduled meals, maintaining attention to nutrient quality versus relying on packaged ’snack’ foods is key. For others, three balanced meals over the course of a day, perhaps with higher caloric density in the morning, could work just fine.
Three Strategies to Sync Eating Patterns to Your Natural Rhythms
1. Ensure sufficient sleep at night. Without sufficient sleep, hunger and satiety signals malfunction, causing us to overcompensate. When the circadian rhythms is out of sync with our lifestyle due to sleep disturbances, that mismatch holds short- and long- term consequences for health, including including increased stress responsively, reduced quality of life, mood disorders, and memory deficits. Try out the Automated Morningness-Eveningness Questionnaire (AutoMEQ) to estimate when your master circadian rhythm starts and ends.
2. Assess for emotional, versus physical, hunger is running the show. When hunger shows up as specific cravings (like chocolate), an emotional cue triggers the desire to eat, and there is an absence of physical cues (growling stomach), those hunger signals may not be in sync with your bodies peripheral clock.
3. Take a close look at your energy patterns. How do you notice you feel 30 minutes after eating? Are your energy levels dropping? Still hungry? Feeling drowsy? These can all be signs that the nutrition you took in was either inadequate or that macronutrients were poorly balanced. Of course, each could be a red flag for not sleeping well-see #1. Experiment with how meal timing impacts your own energy patterns.