It is not wrong advice. It is not dangerous. Exercise is essential for health. From a purely scientific numbers perspective, it has little impact on weight l

It is not wrong advice. It is not dangerous. Exercise is essential for health. From a purely scientific numbers perspective, it has little impact on weight loss in the morbidly obese. The vast majority of impact is from food consumption. Too much Aerobic exercise can be detrimental to weight loss as it encourages metabolic slow down and increases cravings for easy energy. It also has near zero impact on preserving lean body mass. Modest aerobic activity is always healthy, but in the morbidly obese, any more than that is counter productive. Weight lifting on the other hand does have a major impact on preserving lean body mass during a diet, but it also depends on you eating a lot of protein. Without the protein, you’re also not going to be conserving lean body mass. Again, what you eat is the most important. You can lose trmeendous fat , water, and muscle mass purely by eating less. It’s going to be fat-loss with with 20-30 minutes of walking 5 days a week, and some modest dumbbells or resistance band work, and a decent amount of lean protein ingestion.