No. Really, healthy and unhealthy diets aren't binary categories, diets are more are less healthy than others, and there are usually going to be more healthy options than a diet on which you maintain a pre-existing unhealthy excess of body fat.
And, what those diets will have in common, is that you'll lose body fat on them (probably also weight, though that's less certain.)
> Sure, it might be what you need if you start out in an opposite but equally unhealthy state, but in the long run consistent weight loss is fatal.
In the long run, living is fatal, with a 100% mortality rate. But a diet on which you (with your current body weight) are losing weight is not necessarily one on which you will consistently lose weight without limit; one which would maintain a lower but healthy weight will cause you to lose weight while you are above that weight. And would cause you to gain weight if you are below that weight.
Not at all. If you're carrying excessive fat around, you should be modifying your diet in order to shed that excessive fat. If your body composition is healthy, then you should be on a diet that a) is providing both a proper ratio of macronutrients and b) enough calories that you're not losing muscle mass.
Sure, it might be what you need if you start out in an opposite but equally unhealthy state, but in the long run consistent weight loss is fatal.
It might not feel relevant to you, but large parts of the population in the world find themselves in that very situation through no choice of their own.