Photo Credit:
Digital Vision/Thinkstock

How Sleep Affects Your Weight

Improving your slumber habits can make it easier to shed body fat, control appetite and exercise effectively
Written by 
Bob Barnett
Canyon Ranch Reviewer: 

If you’re trying hard to eat a balanced diet, getting plenty of exercise and keeping your stress in check, but you’re still not losing weight—or you’re gaining it—there might be a surprising reason why. Getting a good night’s sleep on a regular basis may be the missing ingredient in your weight-control plan. New research is revealing that too little or poor-quality shut-eye can make it easier for you to put on pounds, and make it harder for you to lose them.

Most people need between seven and nine hours of quality sleep a night. A 16-year study of 68,000 nurses found that those who got five or fewer hours of sleep had a 15 percent higher chance of being obese than those who slept seven or more hours a night. Losing even one night’s good sleep can disrupt the complex harmony of brain chemicals that affect blood-sugar control, body fat, appetite, motivation and energy in ways that make it harder to control weight. Yes, you can catch up on one bad night of sleep, but a pattern of chronic sleep deprivation can make a big difference. Here’s what happens when you don’t get enough quality sleep:

  • Your ability to control blood sugar is impaired. Even if you have a normal metabolism, losing sleep makes you somewhat less sensitive to insulin, the hormone that causes cells to absorb glucose from the blood. When this happens, your body needs to produce extra insulin to keep your blood sugar at the right level. Over time, this stimulates your body to store more fat.
  • Your appetite hormones get skewed. Levels of ghrelin, a hormone that stimulates appetite, go up about 15 percent, while leptin, a hormone that tells you that you’re full, declines by about 15 percent.
  • Your ability to delay gratification is lower. The frontal lobe, which helps you control impulses, is less active when you lose sleep. It’s harder to avoid that piece of cake in the interest of your overall eating plan when your brain hasn’t had time to fully recharge. “The sleepy brain says, ‘Give me carbohydrates, give me fats—now!’” says Param Dedhia, M.D., a sleep and weight-loss expert at Canyon Ranch in Tucson.
  • You have more time to eat. Because you’re up more hours, there’s simply more opportunity to eat. This is especially problematic if those extra hours come at night, since the more you eat later in the day, the harder it is to lose weight. 
  • You’re too tired to exercise vigorously—and enjoy it. “People often ask me if it’s better to catch up on missed sleep or log a workout,” Dr. Dedhia says. “My bias is sleep. Sure, you can work out temporarily with less sleep. But over the long term, if you get better rest, you’ll be more robust in your workouts and you’ll make better choices. If you really want to get the best benefit from your workouts, get your rest.”

Poor sleep can lead to weight gain, but the converse is true, too: Being overweight can make it hard to get a good night’s rest. “With weight gain, you get a bigger neck, and you crowd your airway, causing what’s known as sleep apnea,” Dr. Dedhia explains. You may fall asleep but, for a moment, actually stop breathing. You wake up with a loud snort and catch your breath, interrupting your rest, and then fall asleep again. It can happen hundreds of time a night without you even knowing it.

Getting Proper Sleep

Quality rest, night after night, is key to achieving a healthy weight, but improving sleep takes time. “You’ve built up sleep deprivation—you didn’t get there overnight,” Dr. Dedhia says.

Start by exploring habits that may be affecting your sleep. Each drink of alcohol gives you an hour of being relaxed—and then an hour of arousal during sleep. Drinking caffeinated beverages in the afternoon is another common culprit. “What can wake you up at night? Snoring, apnea, sadness, anxiety, hot flashes or your bladder,” Dr. Dedhia says. Explore your triggers.

More: Bank a Better Night of Sleep

Once you address things that disturb sleep, you can create a sleep ritual that works for you. “Thirty minutes to an hour before bedtime, dim the lights, shut off the electronic screens and perhaps take a warm shower or bath,” Dr. Dedhia suggests. These types of soothing tweaks to your nighttime routine can help you get your Zzzzs—and potentially help you control your weight. The gentlest actions, it turns out, are sometimes the most powerful.

If you think sleep apnea could be affecting you (common symptoms are extreme daytime sleepiness, snoring and dry mouth), speak with your doctor. You may benefit from consulting with a sleep specialist.

Reference(s) 
Harvard School of Public Health
Mayo Clinic
The Sleep Foundation
Stanford University
University of Murcia, Spain
About the author 
Bob Barnett is a New York City-based health journalist, editor and book author who has been writing about nutrition, fitness, psychology and lifestyle medicine for more than 20 years.