Change takes time.
Change doesn't happen overnight.
One day of exercise won't drastically change your body. Just as one day of dieting won't make a difference in your nutrition or diet. But multiple days will! No one who lost weight and has kept it off will tell you that they lost weight successfully in one week. Not even in 30 days. It takes months, sometimes years of slow and consistent progress to transform your body.
I didn't gain 60 pounds overnight (I gained it over several years), so I shouldn't expect to lose it in a day. But there was one time I did. And most people do. If you have several pounds to lose it's going to take you several months. But the key to losing it and keeping it off is striving for slow, steady and consistent progress! Stop fixating at what others are doing. Stop looking for quick fixes. Stop rushing the process. Find a diet that works for you and that you can maintain long-term. Find a movement, exercise or fitness plan that is easy for you at first and that you like to do. Both equally important to start with a positive attitude and mindset and just stick to it till it becomes routine! Take small steps improving yourself mentally and physically. And when you have a bad day don't quit!
3+ months from now, you'll thank yourself! Can you imagine 1 year from now how you'll feel? You'll wonder why you didn't start sooner! Stop fixating on the future and focus on today. What can you do today?