Eat after eight, put on weight?— published: 01-14-2014
There’s an old adage you may have heard: “Eat after eight, put on weight.” And maybe you’ve experienced it first-hand: You noticed that eating those late night pizzas and ice cream really packed on the pounds. But was your weight gain due to timing or just the high calorie counts? According to research in the field of circadian rhythms (CRs)—the 24-hour cycle of your body’s biological, hormonal, and behavioral patterns—it seems that when you eat could be just as important to weight gain as what you eat.
Deep within your brain sits a small cluster of nerve cells—a “master clock” of sorts—that’s responsible for orchestrating your CRs. Each biological system in your body works on a different CR schedule, and the master clock keeps all the schedules in sync. For example, CRs influence your body’s production of the hormones that regulate hunger, as well as how your body uses and stores fats and sugar, ultimately influencing your body weight, performance, and overall health. Other hormones, such as the ones that tell you when you’re full, are switched on or off according to a variety of inputs.
The two greatest influences on how well your master clock is able to keep things in sync are light and food. Light tells your brain how much sleep you get (think: eyes closed, less light). Food (smell, taste, and consumption) tells your body to produce a myriad of chemicals. As a result, staying up late at night, working shifts, and eating at all hours of the day and night—whether voluntarily or due to the demands of overseas deployments, training demands, shift-work schedules, and even parenthood—can play havoc with your circadian rhythms.
In an interesting twist, not only do CRs influence hunger and body weight, but excess body fat and/or a high-fat diet may disrupt CRs. This can lead to further weight gain, culminating in a collection of health problems known as “metabolic syndrome.” In the U.S., regular loss of sleep closely parallels the occurrence of metabolic syndrome. In addition, researchers have found that people who sleep less or have poor-quality sleep are more likely to become obese.
What to do? Make a conscious effort to “normalize” your daily routines as much as possible to maintain regular mealtimes. Whether you choose to eat three regular-sized meals or four to six smaller meals a day, space them out through the daylight hours to take advantage of your body’s natural rhythms. Here are some suggestions to avoid eating late at night:
- Try to eat a balanced dinner at least two hours before you go to bed, and take a walk afterwards when possible.
- Sip on soothing herbal tea or flavored water (without sugar).
- Be aware that watching TV (especially food-related ads) can trigger your desire to eat.
- Sometimes it can help to create new nighttime rituals that don’t involve eating, such as light stretching or yoga, taking a warm bath, listening to soothing music, or reading (or listening to) a book.
But if you find yourself up late at night—whether it’s due to a hard day at work, regular shiftwork, or temporary shifts due to jet lag or an infant’s night feedings—resist the urge to snack out of boredom or to “keep your energy up.” Shift workers should pack or purchase a healthy meal to eat during their work hours—one that includes lean protein and complex carbohydrates such as whole grains, fruits, and vegetables. Eat early in the shift if possible, so you’ll have the energy you need to think and move efficiently. Travelers and parents should look for healthy snacks that follow a similar pattern. And try to limit coffee, tea, and other sources of caffeine to just two to four servings a day.
Of course, eating is just one half of the CR equation. Getting enough sleep is important too, so read HPRC’s overview for great tips on how Warfighters can improve their sleep.