top of page

Why Does Sugar Make Me Sleepy?

Did you know that added sugar causes some of the biggest detriments to human health. Sugar is everywhere, in packaged and processed foods, soda, candy, cakes, cookies, milkshakes, fruit drinks - and that's without all of the chocolates and sweets!

And one major health consequence of eating and drinking these sugary products is to leave you feeling like you need to sleep. So if sugar is supposed to give you an energy boost, you might be asking yourself "Why does eating sugar make me tired?"

woman feeling tired

Are You Consuming Too Much Sugar?

First off are you eating too much sugar? And how much sugar is too much? The World Health Organisation (WHO) recommend no more than 25g (7tsp) for a woman and 35g (9tsp) for a man each day. But studies show that the average consumption is triple that and growing.

Sugar is added to so many things we eat and drink, which is probably why sugar intake was at 77 grams per adult per day in the US, as of 2012.

Added sugars, as opposed to natural sugars, provide no nutritional value and simply add calories to your diet. To avoid negative health consequences, it’s important to stay away from products with added sugar.

Aside from checking nutritional labels for amounts of added sugar, you can usually tell if you are eating too much too much. If you’re craving sugary foods consistently, suffering from acne breakouts, start getting more cavities, or putting on weight, chances are you’re consuming too much sugar.

Another symptom to look out for is feeling foggy right after a meal, when you have a sugar crash due to rapidly fluctuating sugar levels in your body. Finally, if you feel tired all the time, you might have a high sugar intake.

So Why Does Sugar Make You Tired?

The reason eating too much sugar makes you feel sleepy is related to the body’s orexin system. Orexin is a chemical that controls urges to sleep and hunger. When orexin levels are low, it makes you feel tired. When they’re high, you’re more energetic and awake.

People with chronically low levels of orexin often suffer from narcolepsy or obesity, since the chemical influences metabolism too.

When you consume sugar, often you have a feeling of a sugar high. You suddenly feel full of energy and alert. But eating sugar actually lowers your orexin levels. So what you might consider an energy boost actually causes a crash, or a sugar low soon after consumption.

This sugar low is a result of your body expending more energy to break down the sugar. As we’ve mentioned, processed sugar provides no nutritional value and therefore no energy to your body. So your body expels more energy than it takes in when you eat sugar.

The change in orexin levels is also why when you eat a meal high in carbs (which can contain large amounts of processed sugar) you feel like taking a nap afterward. This sleepy sensation makes you not want to move, reducing physical activity. Without this activity, you start putting on weight.

When you constantly consume processed foods and sugary sodas, your orexin levels stay low, keeping you from exercising on a consistent basis.

The Sugar Addiction Cycle

There is also another reason why sugar makes to feel tired and sleepy. This is due to blood sugar levels fluctuating. When you eat sweet foods, you get a blood sugar spike, which causes your body to release insulin to take the glucose from your blood into cells.

However this process usually overcompensates for the sugar spike and leaves too little glucose in the bloodstream, resulting in low blood sugar, or a 'sugar slump'. And the brains reaction to this is to demand a quick source of glucose to bring levels back up again, resulting in cravings and the whole process starting over again.

Illustration showing the sugar addiction cycle

How Can Protein Make You Feel More Awake?

Due to how the orexin system works, eating sugar makes you feel sleepy. But there is a way to combat this tiredness. Studies have shown that just as added sugar can reduce levels of orexin, protein can increase them. That’s why we’re advised to consume protein-rich foods if we want a healthy, lasting energy boost.

It’s also recently been discovered that eating protein in conjunction with processed sugar can offset its negative effects on orexin. Protein’s effects on orexin essentially cancel out the effects of glucose, meaning the orexin levels stay high and keep you feeling awake.

When you feel more energetic, your productivity is increased and you’re more likely to burn off calories. As a result of the research that concluded these facts, protein-rich diets are being linked more to weight loss.


People are consuming too much processed sugar on a daily basis. This leads to weight gain, increased feelings of sleepiness, poor dental health, and a host of other problems. By consuming more proteins, however, you can counter the effects of sugar on drowsiness, potentially improving your overall health.

The best way to fight the negative effects of added sugar, though, is simply to stop its consumption altogether.

There are so many benefits to cutting down on excess sugar, including weight loss, increased energy levels, clearer skin, better sleep and well as reduced chances of getting a whole host of illnesses. I have written a blog here - 17 Amazing Things That Happen When You Quit Sugar.

There are lots of blogs on this website full of tips and advice on cutting down on your sugar intake and if you would like to take part in my 21 Day Sugar Detox you can sign up here.


bottom of page