These surprising foods may make you sleepy during the day, says new study
There are many reasons why you may feel wiped out during the day. But if that feeling becomes more regular and you feel like you're doing everything right – getting enough good sleep at night, exercising regularly, and staying hydrated – it’s worth taking a second look at your diet.
That’s the main takeaway from new research published in The Lancet eBioMedicine. The study identified several molecules in the blood that can be linked to daytime sleepiness, which is a constant feeling of fatigue during the day that interferes with your daily activities. Some of these molecules are found in certain foods, so if you have trouble keeping your eyes open as you sit at your desk, your diet may be playing a role.
Here’s what the study found, along with some advice from dietitians on how to beat that daytime sleepiness slump.
What did the study find?
Researchers collected data on 877 metabolites, which are small molecular products and by-products of your metabolism that are influenced by your diet and hormones. The data was based on blood samples from 6,000 people who participated in the Hispanic Community Health Study/Study of Latinos, along with questionnaire data that looked into how often participants fell asleep during the day in a range of scenarios.
The researchers identified seven metabolites that are associated with excessive daytime sleepiness, but two were most closely linked with specific foods we eat: tyramine, which is found in fermented and overripe foods (like aged cheeses, tofu, kimchi, and salami), and sphingomyelins, which is in eggs, milk, and meat, per the research.
They also identified key nutrients that were linked with less sleepiness, like omega-3 and omega-6 fatty acids, which are often found in foods that make up the Mediterranean diet. Omega-3-rich foods include salmon, walnuts, and flax, while omega-6-rich foods include seeds and nuts, says Scott Keatley, RD, co-owner of Keatley Medical Nutrition Therapy.
Why are certain foods associated with excessive daytime sleepiness?
The researchers didn’t study the reason behind the association – they simply identified the metabolites. But this likely comes down to the way these metabolites behave in your body.
'Some foods, especially fermented ones high in tyramine, can disrupt neurotransmitters like serotonin and melatonin that regulate sleep and wake cycles, leading to more grogginess,' explains Keatley.
Can certain foods help me avoid feeling less sleepy?
Possibly! Foods high in omega-3 and omega-6 fatty acids 'appear protective because they support melatonin production and stabilise circadian rhythms,' Keatley says. As a result, they may improve sleep efficiency and hormone regulation, he explains.
What should I eat to avoid feeling sleepy?
Of course, simply swapping out cheese for smoked salmon at lunch won't cure your midday slump. 'Daytime sleepiness isn’t so simple that you can pin it on one particular food,' says Keri Gans, RDN, author of The Small Change Diet. 'It’s more about overall eating patterns, along with other key factors like sleep habits, hydration, stress, physical activity, and medications that most likely make the biggest difference in how alert you feel during the day."
In general, if you're struggling with daytime sleepiness, it's best to focus on maintaining a stable blood sugar, says Jessica Cording, RD, author of The Little Book of Game-Changers. 'Foods that cause a sharp blood sugar spike might make you feel sleepy because they can cause a spike and then a crash,' she explains. 'That’s what I often focus on when someone says they have daytime sleepiness.'
For the record, foods that contain tyramine aren't naturally bad for blood sugar – this is a completely separate thing. But it's also worth pointing out that foods rich in omega-3s and omega-6s tend to be good for blood sugar stability.
To promote stable blood sugar levels, Cording recommends including protein, healthy fats, and complex carbohydrates in every meal and snack. 'This tends to set you up for stable blood sugar,' she says. In addition, Cording suggests focusing on drinking plenty of water and loading up on hydrating foods like watermelon, berries, or bell pepper. 'Being dehydrated can make you feel sluggish, too,' she says.
While you’re at it, Keatley suggests skipping large meals during the day, as they can cause a spike in your blood sugar, followed by a crash. 'Instead, eat smaller, balanced meals and snacks combining protein, fibre-rich carbs, and healthy fats to sustain energy and keep you alert throughout the day,' he says.
But if you're struggling with excessive sleepiness and changing up your diet doesn’t seem to help, it’s a good idea to check in with a healthcare provider. There are a lot of different things that can cause you to feel this way, making it important to be evaluated.