Key Takeaways
Eating less than 130 grams of carbohydrates daily can make you tired and irritable. Cutting carbs completely can lead to nutrient deficiencies because you miss out on fiber, vitamins, and antioxidants.
Carbohydrates are the body’s main source of energy and one of three macronutrients. Cutting them out can lead to big changes in how the body runs and possibly do more harm than good.
Your Body Will Go Into Ketosis
When you stop eating carbs, your body goes through two main changes.
First, it starts gluconeogenesis, which creates glucose from alternative sources like amino acids from muscle and glycerol from fats.
“While it can be useful for short-term survival, the body shouldn’t stay in that state for a prolonged time, as it could lead to hormone imbalances, hyperglycemia, liver and thyroid processes,” said Samantha Coogan, MS, RDN, LD, director of the Didactic Program in Nutrition and Dietetics at the University of Nevada in Las Vegas.
Within 24 to 48 hours of quitting carbs, your glycogen stores—the body’s backup energy supply—start to run out. To keep the brain and muscles running, the body is forced to burn fat for fuel, known as ketosis.
What Are the Side Effects of Ketosis?
“We cannot survive without carbs,” Coogan said. The human body needs at least 130 g of carbs daily just for basic function, and more if you’re physically active.
Some common short-term effects of ketosis include:
IrritabilityConstipationFatigue“Keto flu”
Long-term ketosis can also lead to dehydration, electrolyte imbalances, and diabetic ketoacidosis, a potentially fatal condition in which ketones build up in the blood in people with diabetes.
Do Low-Carb Diets Help You Lose Weight?
Low-carb diets have been a popular strategy for weight loss for decades, but there’s no clear consensus on what defines a “low-carb.”
Most studies consider carbohydrate intake under 26% of daily calories as low-carb, while nutrition guidelines tend to recommend anywhere between 45 to 65% as normal calorie intake for adults.
One theory supporting low-carb diets, especially for people with diabetes, maintains that increasing protein and fat leads to greater satiety and fewer blood sugar dips, naturally reducing calorie intake.
Some clinical trials show short-term weight loss and better blood sugar control in people with type 2 diabetes, but these benefits often plateau within the year.
“In the long term, the results of people doing low-carb versus other types of plants net out,” Julie Stefanski, MEd, RDN, LDN, FAND, a spokesperson for the Academy of Nutrition and Dietetics, told Verywell.
She added that low-carb diets are so restrictive and hard to stick with that the results are similar to other diets after a year.
Are Keto Diets Good for You?
A well-known low-carb diet is Keto, limiting carbs to just 50 grams daily to keep the body in ketosis.
Even though Ketogenic diets can be helpful for people with diabetes or epilepsy in the short-term, their safety remains a bit unclear since there’s no universally accepted definition, and evidence remains conflicted on their long-term efficacy.
More research is needed before it can be confidently recommended for routine diabetic care.
“The danger doesn’t really come from being in that state for a short-term period. It really comes from avoiding the foods that are nourishing that do have carbohydrates,” said Stefanski.
You can risk access to nutrients found in carbs like:
Vitamin CFolateB-vitaminsFiber
Why Carbohydrates Are Necessary for Your Health
Carbohydrates are essential to your body’s processes, especially with energy use and recovery. For example, one study found athletes recovered better with carbs than with protein alone, showing carbs are just as crucial for muscle repair and growth.
Beyond supplying energy, carbs are also how the body gets fiber, vitamins, and antioxidants. When you stop eating natural carbohydrates, you inadvertently deprive the body of the nutrients it needs to be healthy.
Cutting carbs entirely can raise the risk of cholesterol, kidney stones, poor bone health, gut problems, and even cancer, added Stefanki.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Merrill JD, Soliman D, Kumar N, Lim S, Shariff AI, Yancy WS. Low-Carbohydrate and Very-Low-Carbohydrate Diets in Patients With Diabetes. Diabetes Spectrum. 2020;33(2):133-142. doi:https://doi.org/10.2337/ds19-0070
Firman CH, Mellor DD, Unwin D, Brown A. Does a Ketogenic Diet Have a Place Within Diabetes Clinical Practice? Review of Current Evidence and Controversies. Diabetes Ther. 2024;15(1):77-97. doi:10.1007/s13300-023-01492-4
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