There is an increasing number of evidence that those who stay late have an increased risk of ill health, have more unstable eating habits and consume more unhealthy food.
The latest findings have been reported in the journal Nutrition Developments.
Researchers have found increasing evidence from studies linking conditions such as heart disease and type 2 diabetes to people with evening schedules – a natural preference for evenings.
People who go to sleep later tend to have an unhealthy diet, consuming more alcohol, sugars, caffeinated beverages and fast food than early on. They are constantly reporting more unstable eating habits as they lose breakfast and eat later in the day. Their diet contains less seeds, rye and vegetables and eats fewer but bigger meals. They also report higher levels of consumption of caffeinated beverages, sugar and snacks than those with early preference, who eat a little more fruit and vegetables a day. This may explain why owls are at greater risk of suffering from chronic disease.
Eating food late in the day has also been associated with an increased risk of type 2 diabetes, because circadian rhythm affects the way glucose is metabolized in the body.
Glucose levels, of course, must decrease over the course of the day and reach their lowest point at night. However, as owls often eat shortly before bed, glucose levels increase when they are going to sleep. This can negatively affect metabolism as their body does not follow the normal biological process.
One study showed that people with evening preference were 2.5 times more likely to have type 2 diabetes than those with early preference.
This also affects people who work shifts – especially rotating shifts – as they constantly adjust the body clock to match their working hours. Researchers have found that this reduces their insulin sensitivity and affects their glucose tolerance, putting them at greater risk of developing type 2 diabetes.
The review also revealed interesting trends:
- People's preferences to go up early and go to bed later change at different points in the life cycle. Morning time is more common in children and can occur when a baby is only three weeks old. This changes during childhood. While 90% of children aged 2 years have an early preference, this percentage decreases to 58% by the age of six and is further shifted to an evening preference in puberty. This evening workout continues until an adult reaches the early 50s and begins to return to their morning preference.
- Ethnicity and society can also affect your timeframe. For example, studies have revealed that Germans are more likely to have a nightly preference than Indians and Slovaks. There may also be differences between people living in urban and rural areas in the same country.
- Another study noted that it is exposed to daytime sleep. Every extra hour spent outdoors is associated with 30 minutes of "advanced sleep" and that noise, ambient lighting and overcrowding of urban environments can make people in some areas have a chance of breakfast or evening.
- Researchers also found evidence that night owls would accumulate "sleeping debt" during the working week and would sleep more at weekends to offset this, while early birds had less sleeping differences during the week.
Dr. Almoosawi, Northumbria's brain center researcher, Performance and Nutrition, said, "We've found that your genes, your ethnicity and your sex determine the likelihood of being a morning or evening guy. During adulthood, the sleep of a chronotype is associated with a higher risk of heart disease and type 2 diabetes, and this may be due to poor diet behavior and evening-time diet. Our review also found that people who have worse control of their diabetes are more likely to be evening types. "
"The review has highlighted a significant gap in our understanding of how our biological clock influences food intake in infants, children and the elderly. While most infants synchronize their body clock with that of their mothers as they reach the age of six, we notice that a large proportion of people begin to show signs of developing a nighttime chronotope. Whether physiological changes, school timetables or social programs determine this change, we do not know.