Oh, well, this again is a question that might require a LONG answer…
First, for the general population…Intermittent Fasting (such as what some of us Indians follow) is GOOD. This helps the body to get rid of excess body fat, during the fasting period.
However, fasting, as in eating disorders are obviously NOT GOOD. Things such as Anorexia, Bulimia etc. are VERY BAD for your health. So, eat sufficiently and eat healthy…but do give some rest for your stomach every now and then.
Now, if you are working out regularly and/or you are a world class athlete, then, your nutrition requirements are FAR MORE than the average person.
If you are an underweight person…you then need to eat more to put on a more healthy body weight.
If you are an overweight person, then, you need to go on a calorie deficit. But, you still need to eat adequately (the right quantity of foods) and appropriately (the right kind of foods).
Hope that answers your question…