Is the Keto Diet Dangerous? This is What Really Happens to Your Body in Ketosis

The keto diet is the latest fad to invade diet blogs and weight loss forums. Even though it started out as a medical treatment, it’s now the high-fat, low-carb strategy everyone seems to swear by.

But does ketosis — the process keto dieters strive to achieve as quickly as possible — really cause weight loss? Is weight loss really worth the keto flu headache?

Here’s the biology behind ketosis, why so many people claim it works, and whether or not health experts think it’s a safe and sustainable way to weigh less.

What is ketosis?

Baked egg

Baked egg |

Your body is constantly burning energy to continue functioning. It’s the reason we eat multiple times a day — perhaps in greater amounts when we exercise. Carbohydrates are the first molecules your body burns when it needs energy. When it’s running low on sugar (carbs), it turns to fat as a backup energy source.

During this process, your body produces ketones — which is why it’s called ketosis. These chemicals are made in your liver and sent out into your bloodstream so your muscles and tissues can use them for fuel.

For people without diabetes or who are not pregnant, this tends to happen after anywhere from three to four days of eating less than 50 grams of carbs.

When your body produces ketones, it breaks down your fat stores and promotes overall fat loss.

Does ketosis cause weight loss?

Why do so many people turn to this process in an attempt to lose weight? It’s believed that ketosis is somehow the secret to fast, sustainable weight loss. Nutrition research doesn’t support this claim. But there’s a reason you really can successfully lose weight over time while following keto.

The keto diet helps some people lose weight over time because of:

  • Appetite suppression (you might feel less hungry due to hormone changes)
  • Increased protein intake (compared to a typical American diet)
  • Overall reduced calorie intake (from eliminating high-calorie foods).

But wait. Doesn’t the keto diet increase “fat-burning,” make you burn more calories, and increase your ability to lose more fat? Maybe —¬†at first.

But a study published American Journal of Clinical Nutrition suggests that increased calorie burning, fat loss, and even weight loss are all short-term side effects of starting a keto diet.

Early on in ketogenic diets, stored carbohydrates and fluids mostly contribute to initial — and sometimes fast — weight loss. Fat loss doesn’t happen right away.

Participants in this study did burn more calories and lose more weight. But only in the first few weeks of following the diet. Eventually, their rate energy expenditure — and everything else — fell back down to normal.

This suggests that the keto diet and ketosis might be an effective fat and weight loss strategy in the short-term. But not if you want to lose weight over time and keep it off. More research will provide the insights necessary to determine if keto is the best long-term weight loss solution for certain populations.

Ketosis symptoms and side effects

When you first begin a restrictive diet such as keto, you might experience something people call the “keto flu.” You may feel fatigued, lethargic, and nauseated. This can happen for a number of reasons, but is likely due to the fact that your body prefers it when you eat carbs. You aren’t eating enough carbs. Your body doesn’t like that.

Those who push through these symptoms can achieve ketosis for short periods of time. When you’re in ketosis, you might experience:

  • Decreased hunger
  • Bad breath
  • Fatigue
  • Insomnia
  • Better focus and concentration
  • Digestive problems.

If you live with diabetes, ketosis can progress into something called ketoacidosis. This is when ketosis goes too far, and increases the acidity of your blood to dangerous levels. There’s a reason people with diabetes should not follow low-carb diets. People who follow keto safely will likely not experience this.

Is the keto diet safe?

Keto diet plan

Keto diet plan | ThitareeSarmkasat/iStock/Gety Images

Experts disagree on the safety and effectiveness of ketosis and keto diets. Some believe you shouldn’t follow a keto diet without medical supervision or for long periods of time. Others stick with the argument that the diet isn’t a viable long-term weight loss solution.

But can a keto diet hurt you? Some research has found that people following the diet sometimes develop kidney stones and experience vitamin and mineral deficiencies — which is why some experts caution against following the diet without a doctor’s help.

It’s also possible to misinterpret the diet’s “rules” and end up consuming dangerous amounts of saturated fat (because not all fat is “good” fat). This increases your risk of heart disease, even though some keto enthusiasts boast about its cardiovascular benefits.

But it depends on how religiously you follow the diet and how obsessive you become about losing weight quickly. Ultimately, it’s up to you to decide the extremes you’ll go to in order to lose massive amounts of weight in an unreasonable and potentially dangerous amount of time.

If you take away anything from these points, remember this:

  • Your body enters ketosis when you don’t feed it enough carbs to use as fuel.
  • The keto diet can promote weight loss — but not always for the reasons you might think.
  • Ketosis doesn’t feel great at first — but some people seem to feel better with time.
  • The keto diet is only dangerous if you take weight loss too far.
  • Most health experts don’t believe it’s the best way to lose weight or lower disease risk.

Ketosis is a normal metabolic process that doesn’t usually cause problems for most adults. But it isn’t a miracle weight loss strategy, either. If you can handle the side effects (many people can’t) and think it’s worth it, you’re free to diet as you please.

But if certain symptoms are beginning to interfere with your day-to-day activities, talk with your doctor about more sustainable weight loss options.