In the media, few topics occupy more screen time and print space than body weight and sleep. Newly released statistics showing growing obesity rates and zombie-like images of sleep-deprived citizens routinely make headlines, each time with a different identified cause. Whether it be work stress, family responsibilities, or a favorite primetime reality show, it is not hard to find a reason to put off sleep or reach for a snack.
The viewer interest stems from the fact that we are all affected. At one point this week, odds are we hit snooze, suffered through a 2:00pm lag, or gripped over an extra pound or two gained.
Among the working class, a sense of comradery is felt between two caffeine dependent employees waiting in line for a coveted pre-work java in the wee hours of the morning. An empathetic glance from slumberous eyes shared, both knowing they are starting another day after burning the midnight oil the evening before.
The inverse relationship between the two is acknowledged – we eat too much and sleep too little. Research is now rolling out the “why” behind this vicious cycle, bringing light to a worrisome trend in a fast paced society. Here is what we know…
In a nutshell, what and how much we eat is driven by emotional, cognitive, biological, and environmental factors. Researchers Alyssa Lundahl and Timothy Nelson from the University of Nebreska-Lincoln sum it up by saying, “after a bad night's sleep, the hormone controlling appetite is affected, emotional stress is greater, more food is desired to compensate for lack of energy and impulsivity is increased, all of which affect the amount of food that you would consume in a day.”
The main hormones referred to are known as leptin and ghrelin.
- Leptin is a protein produced by the fat cells within the body. Once made, your fat cells get used to holding a certain amount. Like a gregarious host welcoming guests, a cell feels satisfied when enough leptin is present. If that cell starts having lower than normal levels (like when a person starts reducing how much they eat to lose weight) it begins to feel deprived. Desperate, a series of signals are sent to try and retrieve what it feels it needs. Despite our best efforts, that nagging hungry voice is heard, telling you to reach for a snack to calm the persistent hunger. Leptin can be a bossy hormone, and doesn’t like when the party isn’t packed.
- Ghrelin, essentially, is that nagging voice. Leptin ignites the reaction, and ghrelin is called to duty. Produced by stomach acid, this hormone is an appetite stimulant. Meaning, it tells a body it needs to eat, and won’t stop until it gets enough.
In a perfect world, these hormones would work together like a well-oiled machine. When hungry, we would eat the obligatory amount to satisfy our cells and give our bodies just enough energy. After we burn the energy off through exercise and daily living, we would in turn crave the right portion of food to refuel, creating a precise equilibrium and a healthy body weight. Unfortunately, signals can get crossed or misconstrued, and we all know the world, as beautiful as it is, is not perfect.
Human bodies are complicated organisms. Research is discovering that a person who is overweight or obese for their body frame likely has high levels of leptin, meaning they should feel satisfied and not crave more food. The problem is the brain ignores the plea to stop eating. This phenomenon is known as “leptin resistance.”
Of course, how one becomes overweight or obese in the first place may be due to multiple reasons. We can’t forget the other factors that influence our body weight, those being environmental, emotional and cognitive in nature. We tend to develop habits that cause us to reach for food as well. Stressed? Grab a snack. Smell the fresh baked bread? Try a piece. When consistently giving in to these temptations, combine this with a lifestyle that is not conducive to exercise (desk work, anyone?), and the energy conserved starts to outweigh what is being burned. Even if we were getting enough sleep, if we are not controlling these other factors, we still could be above our healthy body weight.
However, we can’t discount the considerable influence sleep has. Now the question is, how much is enough?
In 2004, Dr. Eve Van Cauter and colleagues from the University of Chicago set out to see how a body reacts when sleep deprived for two consecutive nights. They took a group of 12 healthy young men and only allowed four hours sleep each night. When they measured their hormone levels, compared to their pre-study levels, an 18% decrease in leptin and 28% increase in ghrelin was found.
Van Cauter and crew were also interested in looking at the ratio of ghrelin to leptin (meaning how much “hunger” hormone was circulating compared to how much “fullness” hormone). First they study the men’s levels again, but this time after they were allowed 10 hours of sleep per night, for two nights in a row.
What they found was that after a night with four hours of sleep, the ration of ghrelin to leptin increased by 71 percent compared to a night with ten hours in bed. Bluntly put, with less sleep the men were more likely to feel hunger pains.
Additionally, a questionnaire was given to the men, asking them about their hunger levels. Overall, they reported a 24% increase in appetite, with a “surge in desire for sweets, such as candy and cookies, salty foods such as chips and nuts, and starchy foods such as bread and pasta.” We know these as being energy packed. It is difficult to determine exactly why there was an affinity to this type of food, but it could be related to Lundahl and Nelson’s hypothesis that a double whammy is going on: weakened inhibitions on top of a body craving quick energy to make up for its languor.
The National Sleep Foundation (yes, it exists) also has looked into how much sleep is needed to properly function. It varies with age, but the average adult should slumber for 7 to 9 hours per night. In general, the younger you are the more sleep you need. A growing infant requires an astonishing 14 to 17 hours of snooze time.
When we take this information, and apply it to real life scenarios it can feel like we hit a dead end. The problem of carving the time and “turning off our brains” in order to get enough sleep for some people is insurmountable. Plus, if already overweight, falling to sleep and then staying asleep can be arduous. Health complications like sleep apnea (when a person will momentarily stop breathing during the night) is worse when a person carries excess weight about their trunk and neck area.
So what’s a person to do….are we screwed? I don’t have the answer for you, but I highly suggest starting small. Clinicians recommend turning off artificial lights, removing all distractions from the bedroom, and being under the covers ready to rest by a certain time…no matter what. CNN recommends 6 minutes of bedtime yoga to calm you down and improve your sleep habits (link to full article found below). Everyone’s lifestyle is unique, so a solution will be individualized.
Sleep and a healthy weight are two peas in a pod. They work together to improve your overall health. Set yourself up for success and make sleep a priority, and like well-placed dominos, your health goals will consequently fall into place.
National Sleep Foundation: http://sleepfoundation.org/how-sleep-works/how-much-sleep-do-we-really-need
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