Losing weight is a very annoying thing, because you must pay attention to your diet and strengthen some exercise when you lose weight. Persistence is a very annoying thing, because we all want to play, and sometimes our diet can't go on. In short, losing weight is actually quite tiring and tests people's will. It was easier for me to lose weight in junior high school and high school, because I had constraints and strong willpower at that time.
If you want your wife to stick to it, your encouragement is essential. You can make a plan or goal with your wife. Don't be too ambitious at once. Take your time, such as how many pounds you lose in a week. If you achieve this goal, you should praise her concretely. My motivation to lose weight is that people tell me, Wow, you've lost weight. It's really beautiful. Every time I hear this compliment, I am flattered, and then I am as excited as chicken blood for a while, and I am super motivated to lose weight. You can also buy your wife a gift she likes properly, which is also a very good incentive way.
Besides psychological encouragement, you can also give her some practical support, such as accompanying her to exercise. The best and healthiest way to lose weight is exercise. You can run together at night or do sit-ups with her feet. You can also go to the gym together. I think your wife will be more motivated to have a partner at this time.
Finally, if you want to be a supervisor, you can reward her appropriately, but if she breaks the rules during the reward period, you should remind her to pay attention.
I think if you can do this, your wife will definitely lose weight.