Obesity and being overweight is always associated with unhealthy dietary choices and physical inactivity. Therefore most people go for dieting and exercise. Although these are very important in weight management, we need to look beyond how our body functions.

A Biological clock controls sleep and eating

Most of us know about the woman’s biological clock. But that is not all, our bodies are made up of a number of biological clocks. We have a natural internal clock called the circadian cycle. This clock regulates sleep and wake time by responding to light and darkness. This causes you to be alert during the day and sleepy at night. This clock also controls our eating habits, digestion as well as the release of hormones.

Sleep is a restorative process that is initiated by the brain. According to the circadian cycle, we should eat during the day. When darkness sets in, the information is passed to the brain. The brain releases sleep hormone and you begin to feel sleepy. There are two stages of sleep. The deep sleep stage which important in restoring the body. And the rapid eye movement (REM) stage which helps in memory building.

Hunger controlling hormones

Hunger and appetite are controlled primarily by two hormones. Ghrelin, a hunger hormone is produced in the stomach. This hunger hormone is mostly released before mealtimes. It gives the brain a hunger signal. And stimulates appetite. This increases food intake and promotes fat storage.

The other hormone is called leptin. This hormone suppresses appetite and controls energy balance in the body. When the body has enough energy reserves, the leptin level increases. This signals the brain to stop eating.

Deprived sleep and hunger

Sleep plays an important role in helping energy metabolism. Sleeping for few hours lowers the amount of leptin in our bodies. It also increases the amount of ghrelin. This change in hormones interferes with your body’s appetite regulation. It also interferes with the food choices you make. Research shows that short sleepers prefer to eat calorie-dense foods.

Sleep deprivation means sleeping fewer hours for your age. However, you can go to bed early but not sleep well. Poor sleep or disturbed sleep also has the same effects on leptin and ghrelin.

AGE	RECOMMENDED SLEEP TIME/DAY
0-3 months	14-17 hours
4-11 months	12-15 hours
1-2 years	11-14 hours
3-5 years	10-13 hours
6-10 years	10-11 hours
11-17 years	8-10 hours
18 and above	7-8 hours

How sleep deprivation causes obesity

Sleep deprivation causes changes in our body functions as well as behaviors. This puts us at risk of becoming obese. Some of the changes include:

• Low leptin and high ghrelin levels increase hunger which may lead to overeating.
• High ghrelin level increases preference for high energy foods. These are fatty foods and carbohydrate-rich foods. This results in excess calorie consumption
• Being awake for long results in skipping meals and snacking more. This increases your intake of low-quality diets especially in the afternoon and evenings
• Short sleep time may result in feeling tired and sleepy during the day. This limits the drive for physical exercise and promotes sedentary life.

Things that rob sleep us of sleep

Demand from school, work or leisure activities-especially the night time meetings.  

Excessive use of electronic devices. Many people go to bed with their smartphones or watch TV late. The light from the screens confuses our sleep-wake clock making it difficult to fall asleep.

Shift workers also experience a disrupted sleep cycle. Most shift workers are unable to sleep well during the day.

Light sensitivity. Your eyes are sensitive to even the smallest light. This light causes the brain to be awake all night affecting your sleep quality.

Sleep is a prerequisite to mindful food consumption