Sugar—America’s favorite drug. Eating too much of it can lead to obesity, diabetes, and heart disease. But what happens when you eat too little? Low-carb diets have become very popular in recent years. While these diets often have many beneficial effects on the body, cutting sugar out completely can be harder than you think. People transitioning to the popular ketogenic diet experience sugar withdrawal so often that they even have a name for it: the keto flu.
Sugar is a tricky thing. There are sugars in many of the healthy foods you eat, including fruit, bread, and dairy products. When we talk about sugars from a health perspective, what we are usually talking about are the refined sugar added into things like bread, candy, and soda. This includes table sugar, high-fructose corn syrup, and white flour.
Whether or not you can actually become addicted to, or physically dependent upon, sugar depends largely on your definition of addiction. But it does appear that many people experience withdrawal-like symptoms when they give it up.
Sugar causes a release of endorphins in the brain. These are your body’s natural opioids. It’s possible that your body craves these extra opioids when they’re gone, causing withdrawal. Sugar also causes a release of dopamine, which plays a major role in habit formation.
If you have eliminated all sources of sugar from your diet, including fruit and dairy, then you may be experiencing the keto flu. People on a ketogenic diet consume less than 10% of their calories from carbohydrates per day—which may be less than 20 grams of carbs. Without access to sugar or other carbohydrates, the body has no source of glucose. Glucose is like fuel for our cells, and without it, we begin to starve. The body is forced to turn to its fat stores for an alternative fuel source, which causes a condition called ketosis. Ketosis can be unpleasant.
Signs and Symptoms
Believe it or not, there is an evolutionary basis for your ice cream cravings. Our early ancestors were biologically driven to seek out high calorie foods, such as fruit and honey. Consuming sugars helped our ancestors build up body fat, which was essential for surviving periods of scarcity. The brain rewarded this survival instinct by releasing feel-good neurotransmitters.
Neurotransmitters are the brain’s chemical messengers. There are billions of these molecules at work all the time, sending messages throughout your nervous system that allow you to think, move, breathe, etc.
Addictive drugs like heroin and cocaine produce a high because they either masquerade as neurotransmitters or prompt the nervous system to release a flood of them. These kinds of changes in your brain chemistry lead to dependence, withdrawal, and addiction.
As it turns out, sugar also messes with your neurotransmitters. It triggers a release of endorphins, the natural opioids that are widely recognized for reducing pain after you’re injured and boosting happiness after you exercise. Sugar also triggers a release of dopamine, which is a neurotransmitter linked to cravings.
In animal studies, researchers have found that sugar withdrawal mirrors withdrawal from other drugs, like cocaine and heroin. But animals seem to be more prone to sugar addiction than we are. In one study, when given a choice between cocaine and sugar, cocaine-addicted rats primarily chose the sugar.
For humans, sugar withdrawal is typically less severe. If you cut added sugars from your diet, you may experience:
- Intense cravings for something sweet
- Intense cravings for other carbohydrates, like chips or pasta
Within days of giving up sugar, these symptoms can become so unbearable that we end up binging. Binge-eating is part of a vicious cycle of sugar dependence and withdrawal. After a binge, people often feel guilty, depressed, and angry. So how do they make themselves feel better? They eat more sugar to get those endorphins flowing again!
Endorphins make you feel better while you are eating, but they don’t stick around for long.
If you are on a ketogenic diet, your symptoms may be more severe than those caused by cutting down on added sugars. This drastic drop in carbs causes the body to enter a state of ketosis, which works differently in everyone. You may enter ketosis after cutting your carbohydrates to 50 grams per day, whereas someone else may need to cut them to 10 grams or under. It can take your body a few days to enter a state of ketosis.
Common Ketosis Symptoms
Once ketosis begins, you may notice symptoms such as:
- Muscle cramps
- Bad breath
- Constipation or diarrhea
Basically, ketosis feels like a mild flu. These symptoms typically go away on their own after about a week. It just takes time for your body to adjust to its new reality.
Coping and Relief
How you cope with the symptoms of sugar withdrawal will depend on your goals and reasons for reducing your sugar intake. If your goal is to transition to a ketogenic diet, then you will have to give your body time to adjust.
The ketogenic diet may have health benefits, especially for some people with epilepsy and other neurological disorders. If you are starting a ketogenic diet for health reasons, you may have to suffer the uncomfortable symptoms for a little while. Think of it like an actual flu—you just have to bear it. If your symptoms don’t improve after three weeks, talk to your doctor.
If you are doing a low-carb or keto diet for weight loss purposes, you can consider altering your approach. A low-carb diet has many of the same health benefits as a keto diet, including weight loss. The only difference is that your body will not enter a state of ketosis. Ketosis can lead to rapid weight loss, but it is usually temporary.
To transition to a low-carb diet and put an end to the keto flu, all you have to do is eat some fruit. When the body has access to glucose (from sugary foods) it no longer needs to burn fat for fuel.
It is important to talk to your doctor before beginning a low-carb or ketogenic diet. These diets are usually healthy, but they can be dangerous for certain people. Because these types of sugar-free diets are so restrictive, they can lead to vitamin and mineral deficiencies.1 Vitamins and minerals are essential for growing bodies. For this reason, children and teenagers should not do low-carb diets. Neither should pregnant women.
The long-term health implications of low-carb diets have not been fully explored. Some doctors fear that it could contribute to bone loss and several chronic diseases. To reduce the risk of heart disease, the American Heart Association recommends eating a balanced diet, rich in lean proteins, whole grains, and fruits and vegetables.5
Sugar withdrawal doesn’t really require long-term treatment, because it will pass relatively quickly. The main problem people face is sustaining a low-sugar diet. These restrictive diets are too much for most people, so don’t feel guilty if you fall off the wagon.
The key to successful dieting is to find something you can live with long-term. If going sugar-free for three weeks is going to make you binge next month, try a less drastic diet.
A diet rich in lean proteins, whole grains, fruits, and vegetables will help you sustain a healthy weight while giving the body the nutrients it needs to thrive. Try to avoid processed foods, as they tend to be packed with added sugars. Instead, get your sweet fix from something that contains fiber, like berries, oranges, or apples.