Weight loss surgery is extreme and the only person I personally know who had it died of complications less than 2 weeks later - so should be beyond the last straw you try

If you are on a low calorie diet they are likely trying to get your weight down quickly at which point it will be stabilized and food will be slowly replaced - this time healthy non-processed options

It is a sound method, it works and it doesn't involve cutting you open and bypassing your stomach to do it

Of course you could always say NO - they can't "make you" eat less but then you live with the consequences - it's always your choice