Fiber and saturated fat are associated with lighter sleep

Research studies have shown that reduced sleep amounts can impact food intake and weight. However there is relatively little information on how food intake could impact sleep. Apparently much of the work has focused on self-reported diet and self-reported sleep - in other words, not much has been done in a controlled, monitored environment.

This study attempted to assess whether sleep patterns were different after periods of controlled feeding versus ad libitum feeding - this means that one group was given exactly the same food. The other group was given $25 to buy whatever food they wanted. The controlled feeding was on days 1-4 and the ad libitum feeding on days 5 and 6. The participants sleep was monitored each night with a sleep study.

The results showed that ad libitum food intake was associated with a decrease in slow-wave (the deepest level) sleep and an increase in the time it takes to fall sleep. The greater intake of saturated fats and a lower intake of fiber were also associated with less deep sleep. Additionally increased intake of both sugar and non-sugar/non-fiber carbohydrates was associated with more arousals during sleep. The authors speculate whether a diet rich in fiber with reduced intake of sugars and other non-fiber carbohydrates maybe as useful tool to improve sleep depth and architecture in individuals with poor sleep.

These results are interesting, but the actual data shows what I consider to be small effects. The decrease in slow-wave sleep went from 29.3 minutes to 24.6 minutes per night. This may be statistically significant, but I wonder if this is really clinically significant. The time it took to fall asleep went from 16.9 minutes to 29.2 minutes - arguably a more noticeable change. Of note, there was no subjective evaluation of the patient's perceived sleep quality changes with the two different diets.

Tongue fat and sleep apnea

Apparently your tongue is fat. I mean that there is a normal amount of fat within your tongue muscle. And if you have obstructive sleep apnea (OSA), you may have too much tongue fat. At least according to this recent study. Researchers used sophisticated MRI scans to compare the overall volume and amount of fat in the tongues of overweight men with and without OSA. The results showed that the more obese the subject, the larger the tongue and the higher amount of fat in the tongue. There was also a significant association between belly fat and tongue fat. Patients with OSA had more tongue fat than in the control patients. They also had higher tongue volumes and a higher percentage of tongue fat. There was also an association between the sleep apnea severity and the tongue volume as well as amount of tongue fat.

The amount of fat was greatest in the back of the tongue rather than the front of the tongue in the patients with OSA. This makes sense anatomically because the back of the tongue is involved in blocking off the upper airway during sleep apnea. Another interesting finding was that the researchers examined the chewing muscle and it did not have a higher percentage of fat. This means that when patient's have extra weight, it's not deposited uniformly in the neck and head, but only in certain areas.

Finally, the researchers suggest that the increased amount of fat in the tongue in those with OSA can inhibit the way the tongue normally moves out of the way to allow air to flow.