Drastically switching up your diet always carries the risk of side effects -- which is why it's important to talk to a doctor first -- but low-carb diets shouldn't cause ketoacidosis. This life-threatening condition, which develops when the blood becomes acidic, is generally only a risk for people with undiagnosed or poorly controlled type-1 diabetes. Low-carb diets actually put you in ketosis, a very mild form of ketoacidosis that does not carry the same life-threatening risk.
Low-Carb Diets and Your Metabolism
Reducing your carb intake can whittle your waist, and more restrictive low-carb diets speed up weight loss by affecting how your body generates energy. Normally, your body turns to carbs as the primary source of energy for your cells, and several tissues -- like your liver and muscles -- store carbs in the form of glycogen for almost-immediate energy.
However, on a low-carb diet you're not getting enough carbs to replenish those glycogen stores, so your body turns to fat. It burns fatty acids -- the fat molecules that help make up your fat tissue -- to create ketone bodies, an alternate source of fuel. Because you're creating more ketone bodies for energy, you're burning more fat -- and losing weight.
Low-Carb Diets Cause Dietary Ketosis
Diets low enough in carbs to switch your primary fuel source over to ketone bodies are called ketogenic diets, and those that restrict your carb intake to 20 to 25 grams daily are typically low-carb enough to put you into ketosis. In addition to burning fat, ketogenic diets help you lose weight by controlling your appetite. One study, published in the American Journal of Clinical Nutrition in 2008, found that men following a ketogenic diet ate less and reported feeling less hungry than dieters following a moderate-carb diet that did not put them into ketosis.
Ketosis vs. Ketoacidosis
While low-carb diets are a great way to get into ketosis, they generally won't induce ketoacidosis, a severe form of ketosis typically seen in people with poorly controlled diabetes. Dietary ketosis is harmless, according to a 2004 review published in Journal of the International Society of Sports Nutrition, while ketoacidosis is not.
That's because people in ketoacidosis produce ketone bodies so quickly they overwhelm their natural buffering systems, throwing off their delicate blood pH. Because your organs only work at a certain blood pH level, ketoacidosis can cause coma or even death. If you're noticing early signs of ketoacidosis, like vomiting, abdominal pain, excessive thirst and frequent urination, seek immediate medical attention.
Getting Help With a Low-Carb Diet
Unless you have an underlying medical issue causing ketoacidosis, even a strict low-carb diet should only put you in ketosis. Low-carb diets have their own health concerns separate from ketoacidosis, however. You might feel sluggish for the first few days of your diet -- so be extra careful if you're driving or operating heavy machinery. Following a ketogenic diet long-term may raise your risk of kidney stones or bone fractures, notes the Epilepsy Foundation. You'll also face a higher risk of dehydration, so you'll likely need to increase your water intake.
Talk to a professional before making a major dietary switch, like starting a low-carb diet. They can offer personalized recommendations based on your health and current diet to help you avoid the side effects of a low-carb diet -- and ensure you're healthy and unlikely to experience ketoacidosis due to poorly controlled or undiagnosed diabetes.
- Journal of the International Society of Sports Nutrition: Metabolic Effects of the Very-Low-Carbohydrate Diets: Misunderstood "Villains" of Human Metabolism
- Epilepsy Foundation: Ketogenic Diet
- Harvard Medical School: Diabetic Ketoacidosis
- American Journal of Clinical Nutrition: Effects of a High-Protein Ketogenic Diet on Hunger, Appetite, and Weight Loss in Obese Men Feeding Ad Libitum