What your daughter probably doesn't realize is that losing weight once morbidly obese is practically impossible. If "eating right" was and easy solution, half of our country wouldn't be overweight. It's not about a matter of willpower. Your body biology actively fights against weight loss. It is a battle that only a very few people can win without surgery. It is certainly possible, but weight loss isn't the only factor here. Surgery resolves comorbidities MUCH faster than non-surgery weight loss.
First, let's talk a little bit about why it is so hard to lose weight once you are overweight or obese.
As we gain weight over time, we obviously start adding fat to our bodies. The fat (aka adipose tissue) in our body produces a hormone call lepin. The more fat you have, the more leptin you produce. Your brain reacts to leptin levels to recognize if you are food-deprived (starving). This controls your hunger and metabolism. When you go on a diet and start reducing fat, the amount of leptin in your system starts to decrease. Very often, most of us start out a diet very intensely and we lose fat rather quickly. Your brain sees that you have less leptin in your system and believes you are starving yourself. It is programmed to "defend" the weight it thinks you should be, which is where you were at prior to the diet. So, to defend that weight from further fat loss, it does two things: 1. You get hungrier, and 2. Your metabolism slows down, which decreases how efficiently you burn calories and fat. This is a "double whammy" that is very hard to battle. We can often push through this for a time, but most if not all of us eventually either cave-in consciously and eat/binge, or we start adding calories subconsciously. Your brain and hormones really take over and we are damn near powerless to fight it. Those people who are successful at massive weight loss without surgery are "unicorns." They are practically mythical creatures that are super rare and way outside the norm. Is it possible...sure...is it probable...no.
Additionally, most of the foods people have been eating that have influenced their weight would probably not be considered healthy, and definitely aren't good foods for our digestive system. Our "gut bugs" and gut health have a massive influence on our health and weight. When we are obese, our gut bugs are all out of whack. Our immunity is reduced, we have bile and digestive issues, we have "leaky gut." Our gut is about the biggest immunity organ, which is probably why a massive number of COVID deaths are appearing in obese people and related comorbidities. Our immunity is shot when we are obese. Our guts can actually produce pretty much every single hormone and essential nutrient and chemicals when it is healthy. When it isn't healthy, that also fights against us. Hunger hormones are out of whack, which can compound hunger feelings on top of what the leptin is already doing. It is a massive cascading system that is completely screwed up when we are obese.
These are just some of the reasons it is almost impossible to lose weight prior to surgery.
Okay, the second thing to be aware of:
Surgery can reduce, reverse, and even cure many of these issues, and regular weight loss doesn't always succeed in that regard. Surgery definitely will have a much faster effect on things like hormones and gut bugs much, much faster than non-surgical weight loss. In fact, things like diabetes can go into remission within days after surgery. Hypertension can be lower within days of surgery. Sleep apnea can be improved within days of surgery. Your microbiome (gut bugs) are basically reset to what it would be in a thin person. Your immunity improves almost immediately. All of these things can happen before any significant weight loss, which can really help you focus on building new food and exercise habits. Researchers don't have definitive answers on why all of these changes take place after surgery, but the evidence is very clear that the surgery is much more than just food restriction for weight loss, in fact the food restriction really isn't the important part. It's the hormones. Your brain now sees a much lower "defensible weight" and doesn't put you into starvation mode while you are losing weight after surgery. It's an amazing thing. That doesn't mean you won't be hungry, but I generally eat between 800-1000 calories a day and I experience "normal" hunger, not "starving." That is due to the hormonal signals, not the stomach size restriction.
The last things to be aware of:
All of the benefits of surgery are come with some risk, of course. There is a surgical risk, and although it's low, that risk does exist. In my opinion, however, the risk of remaining obese is a much greater risk for a person's health than having the surgery. It's obviously something to talk with the surgeon about. Obviously, the more obese, the greater the risk, but it's still a smaller risk than all of the potential obesity-related diseases out there (hear disease, diabetes, autoimmune, etc., etc.)
There is also the risk of regaining weight. The surgery does not guarantee permanent weight loss, but it gives you a much better chance to lose it and build good habits for life. That being said, it can easily go the other direction. I personally know people who've had the surgery who as soon as they could start going through the McDonald's drive-through again or started getting fried chicken takeout and eating it during work breaks in the employee bathroom. Self-destructive behaviors and coping mechanisms are not fixed by the surgery. The mental side has to be fixed too, or we are more likely to regain significantly.
In the end, you need to make the decision about your health. I'm sure you value your daughter's opinion, but if you share the benefits of the surgery and how it can more quickly help turn your health around, she should understand and be supportive. I hope she would.
Regardless of what you decide, any steps you take to improve your health and weight would be beneficial, but surgery is going to do way more, much faster than anything else you'd be able to accomplish otherwise.
Best of luck! I really hope you are able to come to a decision that is best for you and your long term health, comfort and quality of life.
Again, these are my opinions based on the research that I've done, mostly drawn from scholarly publications by the University of Michigan and the University of Washington bariatric research centers.
All my best.