This depends on what you actually want out of it. If you just want to diet to lose weight, you should know that the effects are going to be temporary and you’ll end up gaining your weight in the future plus more.
As for changing your lifestyle, this is more long-term. It’s more effective since what changes you will go through will affect your health and body too, unlike diets that are temporary. If you want to see some significant change, your lifestyle will need some tuning up.
Diet fails for long-term weight control
People usually diet mainly because they want to lose some weight and get a thinner body. However, that option is usually temporary, meaning after they get their results, they wold then go back to their usual habits before they dieted. Once that happens, their bodies would go back to their original sizes plus gain even more weight. It isn’t ideal in general, especially for people wanting to lose weight.
Weight maintenance is achieved by lifestyle changes
Because lifestyle changes are done with the purpose of actually CHANGING something you do on your day-to-day basis and not just for a short-term goal, losing weight is a sure-fire guarantee. If you have been eating healthy and then exercising for the sole purpose of wanting to BE healthy and just want to feel like you’re less garbage, then you are going to lose weight and not notice it. In fact, you would even keep and maintain the weight for a long time. Maybe even forever, if you keep at it. As long as you keep in mind to do it all the time until you die, you are guaranteed a healthy and appealing body, while also living longer.
Making this change a necessity
This is where the diet vs. lifestyle change ends, with lifestyle change as the winner. Some people do certain changes in their lifestyle due to changes in their life. There might be a sudden epiphany that happened or maybe health conditions haven’t been looking too good after visiting the doctor. Changing their routines and their lifestyle for the better, no matter how much it sucks for them, had become a necessity. Because they HAVE to, unless they want to suffer. This mostly happens with older people, when they realise that they have NOT, in fact, gotten younger, and that their habits have been tearing at their health down over the years. They change their eating habits and their need to sweat to make a change for their health. They HAVE to. And in the process of them doing so, they lose weight but in the good way.
The lesson here is that you shouldn’t really be on a diet in the first place if you only plan to lose weight. Diets make us miserable. Change your lifestyle instead and be a better you for better benefits.