TIME You Asked

You Asked: Will Eating Before Bed Make Me Fat?

What to eat at night
Illustration by Peter Oumanski for TIME

You’ve been told eating before bed is a no-no. But a little pre-slumber snack can help you sleep more soundly without packing on pounds—if you reach for the right foods.

Especially if you tend to eat dinner a few hours before bedtime or you’re very active (or both), snacking before bed will help stabilize your blood sugar levels during the long, meal-less night, explains Stephanie Maxson, senior clinical dietician at the University of Texas’s MD Anderson Cancer Center.

Why should you care about blood sugar? As most diabetics know, blood sugar and its attendant hormones can supercharge or deflate your appetite and energy levels, as well as mess with your body’s efforts to store or burn fat. “Having low blood sugar in the morning will cause a person to feel sluggish and make it more difficult to get out of bed,” Maxson explains, adding that low blood sugar could also wake you up or otherwise disrupt your sleep in the middle of the night.

Ideally, you want to encourage stable blood sugar levels for optimal health, which will be tough to do if you’re going 10 or 12 or 14 hours without eating, Maxson says. (This is one reason she and many other nutrition experts underscore the importance of eating breakfast.)

“It’s such a big myth that you don’t need any energy for sleep,” adds Cassie Bjork, a registered dietician and founder of HealthySimpleLife.com. Not only can the right bedtime snack provide the fuel your body needs to burn calories while you sleep, but a little grub also calms the release of hunger hormones that tell your body to store fat, Bjork explains.

That said, a pint of ice cream isn’t going to do you any favors. Instead, you should be reaching for complex carbohydrates like whole wheat bread, non-starchy vegetables, popcorn, and fruit, Maxson says. These foods break down slowly, and so help stave off the blood sugar spikes or crashes that could mess with your sleep or appetite, she explains. For athletes, adding a protein like turkey or chicken to a bedtime snack can help with muscle repair during the night while also providing a hit of an essential amino acid called tryptophan, which is beneficial for sleep, Maxson says.

And don’t shy away from a little fat, which can further slow the absorption of carbohydrates into your system, Bjork says. Some avocado or peanut butter—or a splash of melted butter on your popcorn—can help if you frequently wake up hungry or tired.

Just be sure to avoid things like chips, cookies, cereal, or pretty much any traditional dessert food, advises Dr. Joan Sabaté, a professor of public health and nutrition at Loma Linda University. Because fiber and other digestion-slowing nutrients are typically stripped away from these foods during their preparation, your body absorbs them quickly and they tend to cause quick spikes in your blood sugar, which can make it tough for your to sleep, Sabaté explains.

Anything featuring caffeine—yes, that includes chocolate—is also a bad idea at bedtime, Maxson says.

TIME You Asked

You Asked: Is Hot Yoga Good For You—And For Weight Loss?

Hot Yoga
Illustration by Peter Oumanski for TIME

Devoted hot yogis swear by the activity’s many benefits. Others roll their eyes and wonder: Is it even safe to work out at 104 degrees? Here's what the experts say

Start poking around for hard science on Bikram or “hot” yoga, and you’ll find something curious: There’s not much of it. “Considering how popular this is, it’s pretty shocking that our study is one of the very first published research efforts on the subject,” says Dr. Brian L. Tracy, an exercise scientist at Colorado State University.

Tracy and his team have conducted two experiments on the physical effects of Bikram yoga, which involves completing a strict series of poses over a period of 90 minutes in a room heated to 104 or 105 degrees. The first experiment included healthy (but sedentary) young adults with no yoga experience. After eight weeks and 24 Bikram sessions, Tracy says the study participants showed some modest increases in strength and muscle control, as well as a big improvement in balance. They also achieved a slight drop in body weight.

“To be honest, we were pretty surprised by the small size of the weight change, because when you’re in the Bikram studio you feel like you’re working really hard,” Tracy says. “And remember, these were people who didn’t regularly exercise before the study. We were expecting a bigger drop.”

For his follow-up experiment, Tracy hooked up experienced yogis to equipment designed to measure their heart rates, body temperatures, and energy expenditures during a typical Bikram session. That new data helped explain some of those disappointing body-weight findings: While heart rate and core temp climbed significantly (but not dangerously) during the 90-minute session, the participants’ metabolic rates—or the amount of calories their bodies burned—were roughly equivalent to those of people walking briskly.

“I think the immediate reaction is disappointment if you’re a Bikram fan,” Tracy says, adding that, if you’ve spent time reading about the activity online, you might assume you’d be shedding up to 1,000 calories per session. “But that’s not the case,” he says. His research shows men burn an average of 460 calories, while women work off about 330. “I think the heat and the difficulty of the postures combine to alter your perception of the intensity of the exercise,” he explains. On the other hand, one part of your body is getting a major workout, Tracy says. “Heart rates are quite high for the amount of work you’re doing. Quite high.”

Is that something you should worry about, though? “Potentially,” says Dr. Kim Allan Williams, president-elect of the American College of Cardiology. When you’re hot, your heart pumps large volumes of blood to the vessels in your skin where, through a process called convection, sweat is produced. “And it’s actually not the sweat, but the sweat’s evaporation that helps cool you off,” he explains. “Sweat does not evaporate efficiently in those conditions,” he adds.

What does this have to do with hot yoga? The humidity in Bikram yoga studios is supposed to be kept at 40 percent. But in reality, Tracy says it’s tough to know how often that goal is achieved or maintained. As the humidity climbs and your heart keeps working to cool you off, you’re sweating out minerals like potassium and sodium, along with H20, Williams says. “It’s the same for athletes working out in the middle of summer,” he adds. “You have to be mindful of the heat and humidity.”

To protect yourself, both Tracy and Williams say hot yoga practicers need to pay close attention to their bodies. Feelings of light-headedness, nausea, confusion, or muscle cramping—either during or after a yoga practice—are all signs that you need to take a break. That’s especially true for inexperienced yogis, whose bodies aren’t acclimated to the rigors of hot yoga, Tracy explains.

Williams also stresses the importance of hydration and nutrient replacement. “You can’t sweat out a bunch of minerals and then replace them with water alone,” he says. Dangerously low levels of potassium, sodium, and other electrolytes contribute to those scary health risks mentioned above.

Left unanswered are questions about the long-term effects of hot yoga practice, or how people with heart defects or other health conditions might react to the strenuous conditions, Tracy says.

Sweaty bodies aside, most hot yoga fans also praise the activity’s mental and psychological benefits. And a growing pile of research on yoga suggests the practice—and not just the hot varieties—may help lower stress while improving pain management and emotion regulation in ways similar to meditation.

“This isn’t something we’ve studied directly, but I do think there’s an element of mindfulness in Bikram yoga instruction,” says Emily Lindsay, who researches stress and mindfulness meditation at Carnegie Mellon University. Focusing your attention on your breathing and body posture can anchor you in the present moment and foster mindfulness, Lindsay explains. Yoga practice can also provide moments of peace without interruption from your cell phone, email, or life’s other routine distractions. It’s not farfetched to think that these components could offer yoga practitioners some psychological benefits, Lindsay says.

“Millions of people do it, and there aren’t just one or two anecdotal stories about how Bikram changes people’s lives,” Tracy says. “So there has to be something to it.”

TIME You Asked

You Asked: Is Biting Your Nails Dangerous — or Just Gross?

Nail Biting
Illustration by Peter Oumanski for TIME

Social stigma aside, experts say gnawing on your nails could lead to some scary health issues

You do it while you’re reading emails or watching television; the tip of a finger creeps up between your teeth, and you nibble away for a few minutes before catching yourself. Your mom always told you it was a bad habit, and you worry about coworkers eye-balling your shredded digits. But is biting your fingernails actually dangerous?

“Yes, and for a number of different reasons,” says Richard Scher, M.D., an expert on nail disorders at Weill Cornell Medical College and a member of the American Academy of Dermatology.

To begin with, your nails harbor all sorts of germs. In particular, a family of bacteria called enterobacteriaceae — which includes salmonella and E. coli — tends to thrive in the cozy crevice beneath the tips of your nails, Scher explains. When you bite your nails, those bacteria end up in your mouth and gut, where they can cause gastro-intestinal infections that lead to diarrhea and abdominal pain.

Long-term, habitual nail nibblers can also suffer from a type of infection called paronychia, Scher says. Tears or abrasions in the skin of your fingertips allow strains of bacteria or yeast to get inside. Both cause swelling, redness, and a buildup of puss around and under the nail, which has to be drained surgically and treated with antibiotics or antifungal agents, he explains.

If the infection is bacterial, the nail can also become tender and painful. “You’ll see it where every fingertip becomes inflamed,” Scher adds.

The wart virus HPV is also a common infection among nail biters, says Chris Adigun, M.D., a dermatologist at NYU Langone Medical Center. After infecting the fingers, these warts can then spread to your mouth and lips, Adigun adds.

The perils of nail biting also extend to your teeth. “Constant biting can lead to poor dental occlusion, so the biter’s teeth shift out of position or become oddly shaped,” Scher says. Biters also suffer from higher rates of gum disease and infection, he adds.

So how do you quit the habit? For a lot of people, nail biting is a manifestation of stress or psychological disorders.

“Both tend to cause teeth grinding, and your fingernails are a handy buffer.” You’ll have a hard time stopping without help from a psychiatrist or mental-health professional, he says. If your habit is mild, Scher says there are over-the-counter products you can spread on your nails that have a bitter taste. “The taste reminds you not to bite,” he explains.

TIME Germs

You Asked: Is the 5-Second Rule Legit?

The Five Second Rule
Illustration by Peter Oumanski for TIME

When food hits the floor, some say you have 5 seconds to retrieve it before filth hitches a ride. Here’s what germ experts have to say about that

Donut down! You quickly grab your grub, certain you’ve satisfied the 5-second rule with time to spare. But is your fallen food safe to eat?

Past research shows roughly 70% of women would say yes, along with 56% of men, says Paul Dawson, a food scientist at Clemson University who has lab-tested the legitimacy of the 5-second rule. Unfortunately, snacking on stuff that has touched the ground is always a risky proposition, he says.

“I compare picking up dropped food and eating it to not wearing a seat belt,” Dawson says. You could drive a lifetime without wearing a safety belt and never have an accident, but that doesn’t mean you’re safe not wearing one, he explains.

Dawson and his team tested the time it takes harmful bacteria like salmonella to transfer from various surfaces—wood, tile, carpet—to either dry foods (bread) or moist ones (bologna).

Here’s what they found: The length of time food spends on the floor does increase the amount of bacteria that latches on. Also, specific food-floor combinations (especially moist food on tile) result in a greater transfer of germs. But regardless of the snack-surface specifics, a significant amount of unhealthful gunk jumps from the ground to your food pretty much instantaneously, Dawson explains.

“I stand by the zero-second rule,” he says. “If bacteria is present on the ground, it will be transferred to your food.”

Recently, biomedical scientist Anthony Hilton and colleagues at Aston University in the UK repeated Dawson’s experiment with different sickness-causing bacteria like E. coli and Staphylococcus aureus. The results didn’t change.

“The majority of bacteria transfer to the food immediately on impact,” Hilton says. “The quicker you pick up your food, the fewer bacteria will transfer.” But that doesn’t mean a speedy recovery of your fallen treat will keep you safe from germs, he adds.

What about food falling on other surfaces—like your desk at work? It all depends on whether illness-causing bacteria are present, Dawson says. According to a University of Arizona study, the average office desk harbors hundreds of times more germs than the average office toilet seat.

Consider yourself warned.

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