;Resize=(1200,627)&impolicy=perceptual&quality=mediumHigh&hash=49694d9c81fe2aac07ac2ab61b6c9b41364d70c10a772f563f553b3abc90179e "Sleep Disorders: According to researchers, junk food disrupts deep sleep")
A high-fat and high-sugar diet can impair deep sleep – researchers from Sweden have come to this conclusion. They carried out tests with salmon, pizza and chocolate bars, among other things.
If you eat unhealthily, you probably sleep less well. Scientists have now discovered that a diet high in fat and sugar primarily impairs deep sleep. It reduces the delta waves that are typical of this sleep phase, making deep sleep easier and less restful overall. Conversely, the results suggest that a healthy diet could improve sleep quality and even counteract cognitive decline in old age.
Our sleep is divided into different phases. Deep sleep is particularly important for our recovery and physical regeneration. During dreamless deep sleep, it is mainly low-frequency delta waves that can be measured in our brain, which indicates a very low level of activity in our consciousness. As a result, we are less easily disturbed by noises during this time and are more difficult to wake up.
However, external influences such as stress, shift work or eating habits can impair the quality of our deep sleep. When it comes to nutrition, however, it is still unclear what exactly different types of food do to our brain at night.
Sleep tests between salmon and candy bars
In order to find out what influence nutrition has on our sleep, researchers led by Luiz Eduardo Mateus Brandão from the Swedish University of Uppsala have now examined the sleep of 15 healthy men more closely. The participants were randomly assigned to eat healthy for one week and unhealthy for another week. The meals that the research team served them had the same number of calories in both weeks, but the amount of sugar and fat included varied.
That’s how it was healthy eatingwhich included unsweetened yogurt and salmon with vegetables, for example,
- to 9.6 percent out of Zucker and
- to 23 percent out of Fett.
Die unhealthy diet on the other hand, which also had frozen pizzas and chocolate bars, had one
- a sugar content von 17.6 percent and
- a fat content von 44.4 percent.
At night, Brandão and his colleagues monitored the men’s sleep in the sleep laboratory. On the one hand, they measured their brain activity using special electrodes and, on the other hand, they evaluated how long the participants slept in total and which sleep phases lasted for how long.
Junk food interferes with deep sleep
The result, which the team published in the journal Obesity: “We found that the participants slept the same amount of time on both diets. In addition, they each spent the same amount of time in the different sleep phases,” reports Brandão’s colleague Christopher Cedernaes. What had changed, however, was the quality of deep sleep: “Interestingly, we found that deep sleep had lower delta wave activity when participants ate junk foods than when they ate healthier foods.”
Instead of the slow delta waves, which put the body into a deep rest, the researchers were now able to measure more theta, alpha and beta waves during the deep sleep phases, which indicate a higher level of brain activity and consciousness. From these changes it can be deduced that an unhealthy diet leads to easier, and probably less restorative, deep sleep, according to Brandão’s team.
Healthier diet for insomnia?
Similar changes in sleep can also be measured in people who suffer from sleep disorders, or in the elderly in general. Cedernaes therefore recommends that you pay more attention to a healthy, low-fat and low-sugar diet. This could increase the proportion of delta waves during deep sleep, leading to more restful sleep overall. The researchers suspect that this could also counteract cognitive decline in old age.
But the reverse is also true. “It is possible that an even more unhealthy diet in the experiment would have led to even greater diet-related differences, for example in sleep delta performance,” say Brandão and his colleagues. This assumption is also relevant because the population of western countries sometimes eat even less healthily than investigated in the experiment. For example, the average young American’s diet consists of 19 to 23 percent sugar, compared to 17.6 percent in the experiment.
Further research needed
However, it is still unclear whether the diet-related easier deep sleep also has a negative effect on important bodily functions such as memory, the immune system and hormone release. Brandão and his team therefore suggest that these relationships should also be experimentally investigated in the future. According to the scientists, it should also be researched which substances in an unhealthy diet impair deep sleep.
Source: Swedish Research Council
By Anna Manz