Too little sleep is not good, but neither is too much

Finnish researchers have found a link between the number of hours you sleep and how healthy you eat. Specifically the amount and different types of fruits and vegetables.

Going to bed late is quickly associated with an unhealthy lifestyle. The night owl may sleep too little, or may stay in its nest until well into the afternoon. The night owl also often eats a lot and unhealthy. The early bird actually has positive prejudices. The morning person starts their day fresh with a healthy smoothie, a walk or even a yoga session: nice before the day really starts. But is that correct? Morning people really live healthier lives and sleep more or less than evening people?

Researchers from the Finnish University of Helsinki, National Institute for Health and Welfare and the Turku University of Applied Sciences decided to investigate this. To do this, they looked at the role of chronotypes (evening or morning people) and the amount of sleep on how healthy you eat, and vice versa.

Sleep well
Getting enough sleep gives our body the chance to recover from all the activities you undertake when you are awake. If you sleep too little, your heart, blood vessels, muscles, cells, immune system, cognitive skills and memory capacities cannot recover as well and therefore function less optimally. Sleep is also important for the repair of DNA damage incurred. Adults should therefore aim to sleep seven to nine hours per night. But this is becoming less and less successful, according to previous studies. Adults increasingly suffer from insomnia and shorter sleep duration.

Good food
And that’s why fruits and vegetables can help, the researchers reasoned. Exercise appears to have a positive effect on your sleep. And if you want to exercise well and enough, you need healthy food. The idea is that eating fruits and vegetables could lead to better sleep duration. But the other way around, connections have also been found before. Adolescents appear to eat less fruit and vegetables the day after a short night. The Finnish researchers therefore decided to find out how sleep duration affects fruit and vegetable consumption, and vice versa. And whether your chronotype plays a role in this.

To do this, the team used data from the National FinHealth 2017 Study about the eating and sleeping patterns of more than five thousand adult respondents over a period of twelve years. From this they were able to categorize three groups: a fifth of the participants slept less than seven hours per day, three quarters got the recommended seven to nine hours per night and the remaining 3% slept longer than nine hours per night. Most of them did not consider themselves morning or evening people, but something in between. Nearly a quarter considered themselves morning types, and 16% identified themselves as evening types.

Specific vegetables
By comparing that information with the eating patterns of this group, the researchers found that people who slept a normal amount of time ate more fruits and vegetables than the short and long sleepers. That difference was greatest for specifically green leafy vegetables, root vegetables and fruit vegetables (e.g. tomatoes, cucumbers). “Other fresh and canned vegetables such as cabbage, mushrooms, onions, peas and beans showed no significant differences,” the study said. “In the fruit subgroups, a significant difference was observed in the consumption of berries and other fresh and canned fruits between normal and short sleepers.” In normal versus long sleepers, there was only a difference in the amount of apples.”

The researchers hope that governments can use this information to set up interventions to promote healthy eating. “A focus on the subgroups of fruit and vegetables, such as green leafy vegetables and fruit vegetables, can lead to impactful behavioral change.” And that is necessary. Although the World Health Organisation recommends 400 grams of fruit and vegetables per day, it appears that many adults do not achieve this.

Although you should not sleep too much or too little, it does not matter whether you are an evening or morning person for fruit and vegetable consumption, the study shows. Although there are still risks to being a late sleeper, the researchers say. “Previous studies have shown that evening types are often associated with unhealthy dietary behaviors, including a tendency toward obesity-related eating habits.”