Why you get sleepy after lunch, and what actually helps

You get sleepy after lunch mainly because your body clock has a natural dip in alertness in the early afternoon, and a large or heavy lunch tends to make that dip deeper. A short night, a drink with the meal or an hour of sitting still afterward each add a little more.

The dip is normal and you can't remove it, but you can make it much shallower, mostly through what you eat and what you do in the half hour afterward.

Why do you get sleepy after eating lunch?

Two things are at work, and only one of them is the food.

The early afternoon dip

Your alertness through the day is shaped by two forces. One is sleep pressure, which builds steadily from the moment you wake up. The other is your body clock, which pushes back against that pressure through the day to keep you awake until evening. For many people, the clock's push eases a little in the early afternoon before it picks up again. By then sleep pressure has been building for six or seven hours, so you feel the gap.

This is often called the post-lunch dip, but the name is a little unfair to lunch. Studies of it suggest the dip shows up even in people who skip the meal. It may be part of the reason so many cultures have a long midday break or a siesta, and why the hour after lunch is so often the slowest of the working day.

What the meal adds

Eating can deepen the dip. Doctors call sleepiness after a meal postprandial somnolence; most people call it a food coma. Exactly why it happens is still debated. Digestion, the hormones released after eating and the nervous system's shift toward its "rest and digest" mode are all thought to play a part.

One popular explanation is not quite right: that blood rushes to your stomach and leaves your brain short. Your body guards blood flow to the brain closely, so at best that story is a big simplification.

What makes the after-lunch slump worse?

Some lunches, and some days, make the afternoon much harder than others. For most people these are the usual suspects.

The last two rows matter as much as the food. After a good night the dip is usually mild and passes within the hour. After a short one, the same lunch can leave you fighting to keep your eyes open at 2 PM.

What to eat for lunch so you don't get sleepy

There is no special anti-sleep lunch, but a few habits help most people.

• Eat a normal amount. Stop when you are comfortably full, not stuffed. If that leaves you hungry by four, that is what a snack is for.
• Build the plate around protein and vegetables. Eggs, beans, lentils, chicken, fish, tofu or paneer, with salad or cooked vegetables and a modest portion of rice, bread or pasta.
• Prefer slower carbs. Whole-grain bread, brown rice, oats and beans tend to keep people going more evenly than white bread and pastries.
• Go easy on the sweet finish. A dessert or a can of soda on top of a big lunch is a classic route to a 3 PM crash.
• Drink water with the meal. A glass with lunch is one less cause of afternoon fog later.
• Don't skip lunch to stay sharp. It is tempting, and it rarely works. Running on empty tends to make the late afternoon worse, and dinner turns into a rebound.

One easy trick is to split lunch in two. Eat most of it at lunchtime and keep a piece of fruit, some yogurt or a handful of nuts for the middle of the afternoon. A smaller meal is easier to walk away from, and the second half arrives just as the slump would.

If you have diabetes or another condition where what you eat and when really matters, follow your doctor's or dietitian's advice over any general post, this one included.

How do you stop feeling sleepy after lunch?

The dip is shorter and gentler when you deal with it in the first half hour, before you settle in for a long stretch at the desk. This routine takes about fifteen minutes.

1. Walk for ten minutes. Straight after eating, or close to it: around the block, to the store and back, up and down the stairs. A short walk is one of the more reliable ways to feel more awake, and small studies suggest walking after a meal also helps the body handle it. Why a short walk after lunch makes the afternoon easier has the detail.
2. Get some daylight. If the walk is outdoors, this comes with it. Daylight, even on a cloudy day, is far brighter than office lighting, and bright light helps people feel alert. If you can't go out, stand at a window for a few minutes.
3. Drink a glass of water. It is not a cure, but desk days often run short of water by mid-afternoon, and a glass takes one cause off the list. Water and the afternoon slump is honest about where water helps and where it doesn't.
4. Start with something easy. Give the slowest half hour to email, admin, tidying files or a call you can take standing up. Save the hard thinking for later in the afternoon, or for tomorrow morning.
5. Nap, if your day allows it. A short nap in the early afternoon, around 20 minutes, can clear the fog, especially after a short night. Longer ones often leave you groggy. Naps for desk workers covers how to do it at home or in an office.

What about coffee?

Coffee takes the edge off the dip for many people, and an early afternoon cup is reasonable. The catch is timing. Caffeine lingers in the body for hours, so a cup at four can still be working at bedtime, and a worse night makes tomorrow's afternoon harder. If you want one, have it soon after lunch rather than late in the day.

Plan around it

Once you know the dip is coming, you can stop fighting it. Put your hardest work in the morning, or in the late afternoon when many people pick up again, and keep the hour after lunch for meetings, admin and anything you can do on autopilot. Ten slow minutes are less of a problem when you expected them.

A nudge for the slow hour

The dip turns up at about the same time every day, which makes it easy to plan around, and if you use Notchpals, part of the plan can come down from your Mac's notch. Maple, a red panda and one of its Meals characters, makes one lunch visit a day, timed to the lunch hour you give it in Settings. Later in the afternoon Maple comes back for the snack, which is where the second half of a split lunch goes.

MapleSnack time! A little fruit, maybe? Red pandas love fruit. Small bites!

The rest of the routine can come from the same place if your crew covers those areas. Nick, a white spitz from the Movement characters, suggests a short walk once in the early afternoon, right in the slump, and a Water character asks for one afternoon glass. Notchpals can't tell what you ate or whether you walked; it takes your Done on trust. What it can do is catch you at 1:45, hand already back on the trackpad, and suggest a better ten minutes.

When is tiredness after lunch worth asking a doctor about?

A mild slump that lifts after a walk is normal. These are different, and worth a doctor's look:

• You are sleepy after every meal, even small ones, or for hours afterward.
• You nod off at your desk or in meetings, or feel drowsy while driving. If you ever feel drowsy at the wheel, pull over somewhere safe and rest.
• You are tired all day, not only after lunch, even when you sleep well.
• Someone has told you that you snore loudly or seem to stop breathing in your sleep.
• The tiredness comes with other changes, such as being unusually thirsty, needing to pass urine more often, losing weight without trying, or feeling shaky or unwell a few hours after eating.

Tiredness has many possible causes, from sleep problems to conditions a doctor can test for. A doctor can sort through them. Another coffee can't.