A Cleansing or De-tox Method, Not a Weight Loss Method
Fasting has been recommended for years to cleanse or de-tox the body. Some fasts or de-tox diets allow only water. Others permit fruit/vegetable juices and in due course some solid food.
Appraisal of Fasting
A very short term fast (e.g. 24 hours) may indeed help to cleanse the body of toxins. However, it is not a suitable weight loss method, because fasting deprives your body of nutrients and does nothing to help you modify your dietary habits. In fact, if undertaken for several days, a fast can lead to a slow down in your metabolism and an increase in food-cravings. This can lead to weight gain when the fast is over.
The Problem of Fasting
The human body thinks a fast is a famine. So to save energy and preserve fat-stores, it starts to burn calories more slowly. As stated above, this can lead to weight gain when the fasting finishes.
Other Side-effects of Fasting
Unless the fast is very short term, you can end up with low energy, weakness and lightheartedness, without any significant weight loss. Furthermore, the absence of carbohydrates may lead to ketosis – a dangerous build up of ketones that pressurizes the kidneys. This is unhealthy and can be dangerous.
Other symptoms may include:
- Dizziness and faintness
- Bad breath (from ketosis)
Fasting May Cause Loss of Muscle Tissue
A prolonged fast, especially if accompanied by vigorous activity, may cause the loss of lean muscle tissue, including muscle loss from vital organs like the heart. This is very dangerous.
A short fast every few months in order to help cleanse your body, may be beneficial. But using fasting as a way to lose weight is unhealthy and may be dangerous.