Fasting diets for weight loss aren’t all the same, although intermittent fasting, or meal timing, can aid with portion control and works for many. True fasting, where you skip meals for days, isn't a wise strategy. It leads to an extreme calorie deficit, unsustainable weight loss, and unhealthy eating habits long-term. Sustainable weight loss requires balance, so you're better off avoiding these crash diets and quick fixes.