A fad diet is discouraged because it is based on gimmicks that rarely lead to lasting weight loss or help retrain eating and exercise habits.
These diet is sold as the fastest and reliable way to lose weight which isn't the case as it rarely lead to lasting weight loss.
It also doesn't have any standard dietary recommendation hence the reason why it is discouraged.
Read more about Fad diet here https://brainly.com/question/2245667
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