What Really Happens To Your Body If You Stop Eating Carbs?

We live in a world that is increasingly promoting "healthy" lifestyles, meaning that we're pressured more and more to fit into specific molds, adhere to certain diets, and perform myriad workout routines. And let's not forget that weight loss resolutions happen all the time, not just around New Year's. Many resolution setters will be tempted by the fervency frequently shared by adherers to the keto — short for ketogenic — diet. Similar to the Atkins plan before it, keto is a very low-carbohydrate, high-fat diet. Certain keto spinoffs even promote avoiding carbs altogether by adhering to a plan like the carnivore diet, as detailed by the Cleveland Clinic.

You can surely find enough before-and-after photos online to become convinced that cutting out carbs works for weight loss, but at what cost (via Women's Health)? And is losing weight through such drastic restriction sustainable or will you gain every pound back as soon as you reintroduce pasta? Here is everything you need to know about what cutting out carbs really does to your body before you decide whether to jump on the keto bandwagon.

The carb flu

The human body is designed to burn carbohydrates for energy, according to the University of Washington. When you cut off this optimized fuel source, your body is forced to adapt to burning stored fat for energy instead. While this might sound great for fat loss, it can put a significant amount of stress on your body. As a result of making the switch to running on a less-than-ideal source of fuel, you'll notice side effects. These can include feeling fatigued and struggling with brain fog, weakness, dizziness, headaches, nausea, intense sugar cravings, and moodiness (via Intermountain Healthcare).

Since many of the most common symptoms overlap with those of a typical viral infection such as influenza, this period of adjusting to life without carbs is frequently referred to as the carb flu, the keto flu, or the low-carb flu. Depending on how your luck plays out, you might experience these ailments for a just few days, or they may stick around for weeks. This potential for lingering symptoms makes a low-carb diet difficult to sustain and without switching to another form of weight management, any initial weight loss is likely to subside as soon as you return to eating normally, as reported by Insider


If you manage to get through the adjustment period and the uncomfortable symptoms that accompany it, your body will eventually go into what is called ketosis. This process involves the body releasing tiny carbon fragments, known as ketones, into the bloodstream. The presence of ketones in your blood, breath, and urine indicates that your body is now running primarily on fatty acids. It is likely that this backup energy system evolved as a defense against starvation (via Healthline).

Entering and remaining in ketosis takes a toll on your body. Fat is a slower-burning source of energy and you'll feel the difference when you attempt high-energy activities like running. People with disorders of the liver, kidneys, or pancreas—especially Diabetes—can move beyond ketosis into a state of ketoacidosis. During diabetic ketoacidosis, the body is overwhelmed by an uncontrolled quantity of ketones and becomes acidic to a toxic level. The results can be fatal, per the Centers for Disease Control and Prevention. If you do decide to cut out or severely restrict carbohydrates, it is imperative that you consult your doctor first to rule out any serious risks based on your medical history.