Image source: https://tex.org/wp-content/uploads/2014/04/water-weight-gone.jpg
On the other side of the issue, some people say that fasting is safe but only truly beneficial if it's dry, meaning that no food OR fluid is ingested during the fast.
First, let's address the safety issue.
There's an unfortunate misconception that long-term fasting and short-term fasting have the same effect on the body. For some mysterious reason, critics don't read the many well-conducted (and NOT funded by industry and therefore less biased) research on short-term fasts.
Short-term fasting is often referred to as 'intermittent fasting'. Study after study has shown that intermittent fasting is safe and effective for fat loss and other biomarkers of health.
The critics quote data from studies on *long-term* fasting. Long-term fasting is indeed dangerous and unwise, leading to many serious health consequences such as malnourishment, muscle wasting and eventually death.
Short-term fasting usually means going 16-36 hours without food or drinks that contain calories. Studies show that it's safe AND has health benefits that are similar to exercise, including boosting human growth hormone levels.
As long as weight-bearing exercise is done weekly, there is no loss of muscle tissue during a short-term fast.
Nor is there a risk of hypoglycaemia. Blood sugar levels remain in the normal range unless the individual has been medically diagnosed as hypoglycaemic *before* attempting fasting. This surprises many people who experience light headedness when they don't eat. What they're actually experiencing is a drop in blood sugar levels, but not a dangerous one. They may also be feeling the shift the body goes through when it starts to burn body fat for fuel instead of food. Sometimes discomfort may be due to withdrawal from caffeine or other foods that they are actually sensitive to.
On the other side of the fasting debate are people who claim that 'dry fasting' is the superior way to do an intermittent fast. Dry fasting means that you avoid food AND fluid during a fast. This means no water. Advocates believe that avoiding fluid helps the body clear out more toxins and it's the only way to experience the full 'healing' effects of fasting.
So far there is no evidence that dry fasting is superior or even wise. People's hydration levels differ so one person might do fine going a day without water, another might suffer from headaches and other ailments related to dehydration. The humidity of the air, exercise levels, and other factors will influence hydration beyond fluid intake.
Often dry fasting advocates suggest going several days without fluid which can at the very least uncomfortable, and at the very most, dangerous. People who feel bad during a dry fast are said to be 'detoxifying' more than those who don't feel as poorly. There is no evidence, beyond anecdotal reports, that this is the case. Until more research is done on dry fasting, it's best to stick with methods that have been properly studied, as intermittent fasting has.
If you'd like an efficient and safe way to lose fat and improve other aspects of your health, a short-term fast done once or twice a week is worth a try, but until good studies are done on dry fasting, it's wise to only avoid food, not water, on your fasting days.
