that sleep patterns definitely influence eating habits,
such as by increasing energy intake.^6 This effect could
be partly due to the fact that sleep deprivation alters
levels of circulating hormones related to appetite
control, increasing the ratio of ghrelin to leptin and
thus enhancing appetite.^7
Longitudinal and experimental data in the other
direction—showing that diet impacts sleep—isn’t as
abundant. But existing research does suggest that
causality works in this direction as well, and that
dietary patterns and intake of specific foods all can
impact sleep health.^4
This article reviews the key literature on various
dietary patterns and specific dietary components and
how they relate to sleep duration and quality.Fat
Multiple cross-sectional studies have suggested
that higher fat intake is linked to shorter sleep dura-
tion.7-10 A 2015 meta-analysis observed a significant
association between shorter sleep duration and
higher relative intake of saturated fat in particular,
though the association was evident only in individu-
als younger than 65.^11
However, the link between higher fat consumption
and shorter sleep duration isn’t entirely consistent. A
cross-sectional analysis of a subset of participants
from the National Health and Nutrition Examination
Survey (NHANES) 2007–2008 found that short sleep-
ers (those who slept between five and six hours per
night) had a higher intake of total fat than normal
sleepers. However, very short sleepers (those who
slept less than five hours per night) had lower intake
of total fat than normal sleepers.^12
While this research examined the relationship
between fat intake and sleep duration, other research
has suggested that fat intake may be related to sleep
quality. For example, a 2015 analysis of middle-aged
Finnish men by Tan and colleagues found that higher
fat consumption was associated with insomnia.
Although few randomized controlled trials have examined the
impact of diet on sleep, one noteworthy trial led by researchers
at Columbia University found that saturated fat intake negatively
impacted sleep quality. In the trial, which included 26 adults aged
30 to 45, participants consumed a controlled diet for four con-
secutive days, after which they were allowed to self-select their
food on the fifth day. Greater intake of saturated fat on that final
day of ad libitum selection predicted less slow-wave sleep.^13Protein
Like fat, protein intake has been linked to both sleep dura-
tion and sleep quality. In NHANES 2007–2008, very short sleep
(less than five hours per night) was associated with lower total
protein intake,^12 and both short and long sleep were linked to aslightly lower percentage of energy coming from protein com-
pared with normal sleepers.^14 Among young adult women, those
who reported sleep duration of less than six hours had lower
energy intake from protein and higher energy intake from car-
bohydrates relative to normal sleepers.^15
As for the association between protein intake and sleep qual-
ity, a cross-sectional analysis of 4,435 nonshift workers in Japan
found that low protein intake (<16% of energy from protein) was
linked to difficulty initiating sleep and poor quality of sleep. How-
ever, high protein intake isn’t necessarily desirable either. In the
Japanese study, a diet containing >19% of energy from protein
was associated with difficulty maintaining sleep.^16
According to Essra Noorwali, MSc, PhD, a researcher in the
Nutritional Epidemiology Research Group at England’s University
of Leeds, further research is needed, but the effects of protein on
sleep are “promising” and likely due to the amino acid tryptophan,
which is a precursor to the sleep-regulating hormone melatonin.^17Carbohydrates
Epidemiologic research on the link between sleep and carbo-
hydrate consumption has been conflicting. In several studies, low
carbohydrate intake has been associated with insomnia, obstruc-
tive sleep apnea, and difficulty maintaining sleep.16,18 However,
a cross-sectional study of middle-aged Japanese women found
a significant trend toward poorer sleep quality with increased
carbohydrate consumption.^19
In the case of the Japanese study, the quality of carbohydrate
appears to have been significant in mediating this association.
High intake of confectionary and noodles was associated with
poor sleep, and poor sleepers with the highest carbohydrate
intake consumed more of these foods than did good sleepers
with high carbohydrate intake.^19
In regard to the connection between carbohydrate intake and
sleep duration, some research has found an association between
higher carbohydrate intake and shorter sleep duration in both
younger and middle-aged adults.11,15 By contrast, in a sample
of Chinese adults, sleep duration of less than seven hours was
associated with a 1.8% lower carbohydrate intake compared with
normal sleepers.^10
Besides cross-sectional studies, several experimental stud-
ies have examined the relationship between carbohydrate intake
and sleep quality. Multiple trials seem to suggest that dietary
patterns lower in carbohydrates result in reduced REM sleep
but increased slow-wave sleep.20-22
Carbohydrate intake also may affect sleep onset latency
(ie, the time it takes to fall asleep).23,24 In a four-day controlled-
feeding test of the effects of individual macronutrients, a high-
carbohydrate diet decreased sleep onset latency as compared
with high-protein, high-fat, and control diets.^23
The impact of carbohydrates on sleep onset latency has been
tied to the presence of the amino acid tryptophan.^4 The data
on carbohydrates and sleep is still limited, however, and none
of the existing randomized controlled studies have examined
long-term effects.Lınk
Between
ZZZs
& Eats
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