Ask HN: How to deal with after lunch fatigue?

A relatively low hanging fruit that can help: chew more! This will both help with digestion, so your body will invest less energy, and secret more satiety hormones, so you will even eat a bit less without being hungry.

I moved to very lightweight lunch meals.

I start my day with some breakfast to carry me until noon, then have a small lunch like a salad with a bit of protein. I almost never feel tired after that.

Carbs give you energy, high fiber foods make you less hungry over longer periods of time, and protein makes you drowsy if it's more than a little. Start the day with some carbs (like rice!), eat some vegetables and low amount of protein and carbs for a small lunch, and then get the rest of your protein at dinner. This of course varies from person to person but you can only find the mix that works for you through trying.

Get your 8 hours of sleep in addition to this, and you're golden.

Another tip which I know is super annoying to hear, is that some exercise can be very energizing. A little bit goes a long way.

There is a fallacy that you have to be loaded on carbs to be productive. I find MCT oil[0] gives me laser focus, and typically make egg mayonnaise which I make with olive oil, grass-fed butter, MCT Oil, and vinegar. The old way of: 'Go to work on an egg' is brilliant advice.

[0] https://shop.bulletproof.com/collections/mct-oil

Chew properly, make sure you’re drinking water throughout the day, and have a lunch that has nutritional value. Avoid carb heavy meals or take out food.

I usually have some leafy greens mixed with beans and a light dressing. Enough to not feel hungry but also not feed “full”. Drinking 8 oz of water helps with that.

1 - after-lunch fatigue is often caused by an interruption in one’s ultradian rhythm, often induced by early consumption of caffeine. Wait a full ultradian cycle (90 minutes) after waking before caffeine consumption in the morning. Even for longtime early morning coffee drinkers, it’s actually pretty easy to break the habit and delay caffeine intake. (Early morning concentration does not suffer.)

2 - get early morning sunlight to ensure well-functioning internal clock and dopamine/cortisol/serotonin function.

3 - take a real rest after midday meals. Go for a walk. Do nothing. Hangout with friends. Read. Rests must be real (no social media) to be effective.

4 - if you like what you’re working on make the midday meal light and keep after it.

On a final note, oftentimes it is appropriate to shift into less-focused work later in the day. Humans experience less dopamine and less cortisol starting around midday, and serotonin or unfocused joy becomes a dominant force. (For me this happens something like 7 hours after waking. I do more abstract design work, write, connect with people, read, broaden strategic perspective, do whatever work I find most fun, or stop working altogether.)