In order to understand why the Keto Diet is bad long-term, you need to understand how the Ketogenic Diet works in the first place. A Keto Diet is one which is very low on carbohydrates, which is one of the main sources of energy for the body.
During digestion, the body breaks down foods rich in carbohydrates and produces glucose, which is used as the main fuel source for energy to run the body. When the body is deprived of carbohydrates, it switches its fuel source from glucose to fat and ketones. This stage is known as ketosis, where the body relies on fat and ketones as its main fuel source for energy. The body goes into this state usually within 3 or 4 days after you start the diet.
This switch in diet is normally accompanied by various symptoms such as irritability, headache, concentration problems, dizziness, bad breath, stomach pains, difficulty sleeping, constipation, confusion and many others. For this reason, these symptoms are also called the Keto Flu.
Normally, the symptoms of the keto Flu subside within a week, and the body begins to lose weight. The weight loss can often be quite visible and dramatic. Most people could be very happy to see the diet working after all. But this can come with some negative effects that can be bad or even dangerous to your health.
You need to understand that your body needs a balanced diet for healthy living. As soon as you start deriving your body of certain kinds of otherwise healthy foods, there is an imbalance created in your system that can give rise to nutrient deficiencies. If your body continues to experience nutrient deficiency on a long-term basis, it can pose a number of risks to your general well-being.
Nutrient deficiencies can result in dehydration and electrolyte imbalance, which is quite well-documented. A Ketogenic Diet also tends to be low in fiber and minerals like potassium, calcium, magnesium, and vitamins A, B and B6. Therefore, you need to increase your water intake. You would also need to consult your physician for appropriate supplementation to help avoid a long list of health conditions that can accompany nutrient deficiency.
But by far, the biggest problem with this form of diet is sustainability. When you deprive your body of your favorite foods, your body might begin to increase cravings, forcing you to give up your diet. And when you go back to eating normally once again, the rebound weight gain could be dramatic as well. This could be accompanied by side effects again, as your body begins to readjust back to glucose as its main fuel source for energy.
For all these reasons, the Keto Diet cannot be used as a long-term solution for weight loss. If you wish to lose weight in a hurry for the short term, and are ready to go through uncomfortable symptoms, then perhaps you can try this solution. But it could be a bad idea to go for this lifestyle as a permanent and long term solution for losing weight.