Weight management is tough for many of us, even when the equation seems pretty simple: Burn more calories than you consume and you’ll lose weight; eat more than you burn and you’ll gain weight. Not particularly complicated, right?

Well, not so fast.

Energy balance is key when trying to maintain your weight and the “calorie in, calorie out” rule is certainly the mantra when embarking on a weight-loss plan. However, as a registered dietitian in private practice, I‘ve found that it’s important to look at all kinds of factors that can affect this equation. For example, my clients are often surprised when I ask about their sleep patterns. After I explain how their busy lives and lack of sleep may interfere with weight management, the pieces of the puzzle begin to make more sense.

To fully understand the connection between sleep deprivation and weight management, it’s helpful to evaluate the sleep habits of Americans and how they’ve changed with rising overweight/obesity rates. Unpublished data from a 2004 National Health Interview Study found that the number of adults in the United States averaging less than six hours of sleep a night has dramatically increased in the past two decades.

In a 2000 Omnibus Sleep in America poll, it was documented that the average adult admitted to seven hours of sleep per night. In addition, 33 percent of respondents claimed to sleep at least eight hours per night during the work-week, while 33 percent reported to sleep less than six and half hours. For shift workers, 49 percent stated that while working, they slept six and a half hours or less. Alternatively, a century ago, the average American slept about nine hours a night (Webb and Agnew 1975).

Keep in mind the decline in sleep as you consider the information in adjacent visuals depicting the problems that the United States is encountering with the rise of overweight and obesity.

Upon evaluating the data, there appears to be a parallel growth among obesity and sleep deprivation. Recent research has backed up this notion. In 2001, Shigeta et al. studied 321 men and 132 women, and found that those who were sleeping less than six hours per night and remained awake beyond midnight had an increased likelihood of obesity. In 2005, Voronoa et al. found that when analyzing 924 patients, women slept more than men, and overweight and obese patients slept less than those with a normal body mass index (BMI). Patients reported less sleep in a nearly linear relationship from the normal through the obese group. However, the trend of decreasing sleep time was reversed in extremely obese patients.

The suggestion that the U.S. obesity epidemic might have a corresponding decrease in the average number of hours that Americans are sleeping was confirmed in a 2005 study of a nationally representative sample of about 10,000 adults. The study found that people between the ages of 32 and 49 who sleep less than seven hours a night are significantly more likely to be obese. The self-reported sleep durations at a baseline of less than seven hours had higher average BMIs and were more likely to be obese than subjects with durations of seven hours. Sleep durations of greater than seven hours were not consistently associated with either an increased or decreased likelihood of obesity in the cross-sectional and longitudinal results. Each additional hour of sleep at baseline was negatively associated with change in body mass index over the follow-up period, but this association was small and statistically insignificant. These findings support the hypothesis that sleep duration is associated with obesity in large, longitudinally-monitored US samples.

We are not only seeing rising obesity rates among adults, but children as well. So, it’s important to look for any parallel between sleep and children’s obesity rates. Upon reviewing the data, it does appear that children are not excluded from this data. A study of over 9,000 seven-year-olds whose growth had been followed since birth studied factors in early childhood that may later cause obesity. The results of the study show that children aged 30 months who slept the least were more likely to be obese at age 7 than children who slept more (Reilly et al., 2005). Sekine et al. investigated more than 8,000 six- to seven-year-olds in Japan by questionnaire and collected their heights and weights. They found that parental obesity, physical inactivity and long TV watching were significantly associated with childhood obesity — no big surprise there. Also, a significant relationship between late bedtime or short-sleeping hours and obesity was found, whereas wake-up time was not significantly related to obesity. This finding remained significant after adjustment for age, sex, parental obesity, physical activity, TV watching, frequency of breakfast and/or snack intakes.

The causes for the correlation between inadequate sleep and obesity could be many. Some scientists speculate that sleep deprivation might be disrupting hormones that regulate appetite. Other scientists hold that the physical discomfort of obesity and related problems, such as sleep apnea, reduce an individual’s chances of getting a good night’s sleep. Let’s take a closer look at the research.

Sleep restriction causes a cascade of events that appear to disrupt the multiple actions involving glucose regulation and brain and hormonal functioning that take place during normal sleep patterns to keep the body in balance. Researchers have found many correlations, including changes in growth hormone, insufficient thyroid stimulating hormone (TSH) increase, poor glucose tolerance, increased cortisol levels and changes in the hormones ghrelin and leptin, which both have a strong connection to appetite regulation.

Spiegel et al. completed a small study of young, healthy, normal-weight men in 2004. The participants were put under a sleep restriction phase (four hours of sleep on two consecutive nights) and a sleep extension phase (slept up to 10 hours on two consecutive nights). During the sleep restriction phase, leptin (the hormone that signals the brain to stop eating) levels were 18% lower, while ghrelin (the hormone that signals the brain to keep eating) levels were 28 percent higher than they were during the sleep extension phase. Also, mean hunger ratings were 24 percent higher than they were during the sleep extension phase. Appetite ratings were also significantly higher after sleep restriction; especially for high carbohydrate, energy dense foods such as sweets, bread, pasta and potatoes.

A 1999 study by the University of Chicago Medical Center shows that sleep deprivation severely affects the body’s ability to metabolize glucose, which can lead to early-stage diabetes (Spiegel et al., 1999). The researchers limited 11 healthy men in their 20s to four hours of sleep for six straight nights, bringing them to a nearly pre-diabetic state. The subjects were 40 percent less able to clear glucose from their blood and 30 percent slower in releasing insulin than when they were allowed to sleep for 12 hours. The researchers concluded that four hour sleep nights gave the young men the insulin sensitivity of 70- or 80-year-olds.

A review article by Patel and Hu in 2008 resulted in the following conclusion: “Short sleep duration appears to be independently associated with weight gain, particularly in younger age groups (children).”

In 2005, Spiegel noted that “…chronic sleep loss, behavioral or sleep disorder related, may represent a novel risk factor for weight gain, insulin resistance, and Type 2 diabetes.” Carl Hunt, MD, director of the National Center on Sleep Disorders Research at the National Institute of Health summarizes the issue well: “It’s no secret that we live in a 24/7 society. There are many more opportunities to do things other than sleep: 24-hour cable TV, the Internet, email, and long work shifts. People just don’t realize how important sleep is, and what the health consequences are of not getting a good night’s sleep on a regular basis,” Hunt tells WebMD. “Sleep is just as important for overall health as diet and exercise.”


Written by Amy Culp, RD, CSSD, LD. Amy, co-owner of sCULPture Nutrition & Fitness, LLC, is nutrition therapist and Board Certified Specialist in Sports Dietetics with a private practice in Austin. She can be reached at amyculprd@sCULPturetexas.com.

Many thanks to the content contributions of Ryan D. Andrews, MA, MS, RD, CSCS, CISSN ACSM, Health/Fitness Instructor, NSCA Certified Personal Trainer, Dietitian/Exercise Physiologist/Director of Research – Precision Nutrition, rdandrew@kent.edu


MORE TIPS FOR BETTER SLEEP
1. Set a schedule for bedtime and waking time
2. Develop a bedtime routine
3. Relax before sleeping — deep breathing, meditation, prayer
4. Eliminate caffeine, nicotine, alcohol or heavy, spicy, sweet foods at least 4 to 6 hours before bedtime
5. Exercise regularly, but not right before bedtime
6. Use a noise machine for white noise or other relaxing sounds
7. Keep your bedroom quiet, dark and comfortable
8. Avoid watching TV (consider removing them from children’s rooms), eating and discussing emotional issues in bed