Bariatric surgery is currently the only real effective treatment. With GLP agonists like semaglutide having similar effects at least in the near term.
This baseless assertion is simply outright wrong, and utterly absurd on so many levels.
* https://www.acpjournals.org/doi/abs/10.7326/0003-4819-133-2-...
* https://www.nature.com/articles/0800499
Please don't spread misinformation.
Weight loss from diet/exercise will definitely persist for a year or even a couple.
Also specifically about exercise your study says "[Weight] did not change in the exercise without weight loss [group]"
That only happens if the patient relapses into his previous unhealthy lifestyle.
You can't simply follow a poor high calory diet and a sedentary lifestyle and still expect zero consequences from your actions. If your problem is behavioral then you fix it by fixing the problems in your behavior.