Caffeine, metabolism and sleep
You probably know that caffeine keeps you awake. But what you might not realize is how long it sticks around and how much it can mess with your metabolism even hours after your last sip.
Avoid caffeine after 12pm
You might notice Limbo members follow an unofficial no caffeine after midday rule**.** That’s not because caffeine is “bad” but because the effects on your sleep can be subtle, delayed, and highly individual. Some people can drink espresso after dinner and fall asleep. But most will sleep worse, whether they feel it or not.
The only way to be sure? Give your body time to clear it.
Caffeine has a long half-life
Depending on your genetics, liver function, and other factors, caffeine can take 4 to 12 hours to leave your system. And even a single late-afternoon coffee can cut an hour or more from your total sleep time.
That means lower energy, more hunger the next day, and reduced willpower.
Poor sleep = poor glucose control
Missing even a little sleep increases:
- Cravings (especially for sugar and carbs)
- Hunger (via ghrelin, the hunger hormone)
- Insulin resistance (making weight loss harder)
- Emotional reactivity (less impulse control)
- Energy crashes (which lead to more caffeine)
It becomes a vicious cycle that can start with a well-meaning 3pm coffee.
Strategies for managing caffeine
Here’s how to get the benefits without the metabolic cost:
✅ Stick to morning coffee only
✅ Try green tea for a gentler lift (and antioxidant benefits)
✅ Watch out for hidden caffeine in chocolate, soft drinks, energy drinks
✅ Try decaf or water if it’s more about habit than hit
✅ Replace the afternoon crash with a brisk walk or even a cold shower
You don’t have to quit coffee, in fact it can be useful as an appetite suppressant if you're delaying your breakfast. But you do need to know when to stop for the day.
Cut caffeine by 12pm, sleep better, crave less, and reset faster.