“Not only your memory is affected, but your ability to solve problems is also hindered, in addition to your alertness, attention, concentration and judgment. Your brain isn’t as efficient as it should be.”

A 2013 study from the University of California, Berkeley, in the US found that during sleep, your memories are essentially moved from short-term holding to long-term storage. When you get poor quality sleep, those memories don’t move to the prefrontal cortex for storage and they’re forgotten.

So, staying up all night to study is one of the worst possible moves. “When you pull an all-nighter – even just one – the lack of sleep can have tremendous effects on your mind and your body,” says Greuner.

Screwing with your circadian rhythm

The circadian rhythm is your body’s cycle that tells it when to wake up, go to sleep, and perform many other functions.

“Your body relays ‘messages’ to your hypothalamus all day long, which then sends out the hormones that make you feel tired, hungry, etc,” explains Greuner. “If you stay up all night, these messages are out of whack, making you feel downright terrible.”

So, you’ll not only feel tired, but you’ll be hungry, achy, and moody as all get-out.

It also affects your eating habits. “Sleep deprivation affects eating behaviour and glucose metabolism. Specifically, levels of ghrelin [a hormone that signals hunger to your body] increase whereas levels of leptin [a hormone that signals a full ] are reduced,” says Kimberly Fenn, Reverie Sleep Advisory Board Member and Associate Professor of Psychology at Michigan State University.

“Thus, after an all-nighter, you are more hungry than normal and your body feels less full. In addition, your body is less able to metabolise glucose, similar to being in a pre-diabetic state.”

Not great news, since the all-nighter diet often consists of Flamin’ Hot Cheetos and M&Ms. All that junk food gets metabolised poorly, making it even harder to stay awake and oddly enough, hungrier for more Cheetos.

When all-nighters become habit

Physical and mental issues show up right away with sleep deprivation. But if you don’t get enough sleep on a regular basis, the effects are much worse.

“Long-term sleep deprivation can lead to increased stress levels, diabetes, obesity due to increased ghrelin, strokes, high blood pressure, and depression,” says Fenn.

Greuner adds that heart attacks, heart disease, irregular heartbeat, heart failure, stroke, diabetes, and high blood pressure can also come from chronic or ongoing sleep loss. But if you’re in the habit of pulling all-nighters regularly, you’re putting yourself at risk.

The morning after

“If you must pull an all-nighter, try not to get through the day solely on excess caffeine. Drink plenty of water, eat healthy, and try to sneak in a short nap, if possible,” says Greuner. Opting for nutritious food and not junk when you’ve been up for 24 hours is a mighty task, but if you stay hydrated and nourished, your body will recover much faster.

“It can take weeks for the body to recover from the circadian rhythm disturbance that occurs with sleep deprivation,” says Nesheiwat. After staying up all night, it’s important to get back to a regular sleep schedule as quickly as possible. If you feel a little off for a few days, it’s just your body getting back to normal.

Though a college kid somewhere is pulling an all-nighter as you read this, don’t let it be you. Consider yourself older and wiser: skip the moody, hungry, foggy hangover, and get a good night’s sleep already.