I believe the reason why biggest loser dieters all yoyo’ed was because they are all probably hyperinsulinaemic. It’s highly unlikely that humans can get to be 300+ lbs without being insulin resistant. So these people make enough insulin to inhibit lipolysis if they eat carbs and protein.
What they do is they eat hypocaloric amounts of carbs and protein (low fat of course), and they increase their apparent exercise. This is the precise of Calories in: Calories out.
But they can’t use much stored energy (because they are hyperinsulinaemic and eating things that make them make even more insulin) and they have less energy coming in, and they are doing more apparent exercise … so what happens?
Well the law of thermodynamics is a thing … so their bodies drastically reduce essential services (BMR plummets). And when that threatens survival, only then does their insulin drop a little and they can burn a little more body fat. But the underlying cause - the fact that they make a LOT of insulin for the same response as a normal person does not change.
What happens as soon as they slow down on the restriction, they start putting weight on again back up to meet their level of insulin resistance and because their MBR is now in the toilet there is a good chance they over correct and end up weighing more.
The answer is we need to lower insulin, and our bodies will do the rest because they are a significantly better calorie counters than we ever will be. We lower insulin by eating less foods that require insulin to be made (carbs and protein), spending less time eating (intermittent and extended fasting), building muscle (lifting) and then using it (HIIT) as a way to clear insulin, and using drugs that reduce insulin resistance (metformin, Berberine).