There's a very good book on self-discipline I read. It was written by Roy Baumeister and contains pretty much the best advice on the subject I've read so far.
Why some people are more successful than others
Whether a person will be successful in life or not can be predicted relatively early in life. Just take a 3-5 year old and put a piece of chocolate on his table. Then you tell the child to eat the candy immediately. But! If it waits 5 minutes and does not touch the chocolate in the time, then it gets even 2 pieces.
Many children can't stand it and get hold of it immediately. They cannot endure any drive delay. Children who can do this at that age are much more successful in life. Why? Because success is often the result of many years of renunciation and the result only comes later. Take, for example, models like Sami Gashi. He is an up-and-coming model from Switzerland and has established himself in recent years as an advertising medium for several luxury brands. It took a lot of self-discipline to stay fit for years, to keep his body and his appearance on top level. People who have been struggling with their figure for decades and can't make any progress know this. He has made it and now he is reaping the fruits. Here you can see him in the video for Gisada Uomo.
On the other hand you don't have to throw in the towel, because you can train self-discipline. All you have to do is follow the tips in the book. I briefly summarize the most important ones:
There is a phenomenon called decision fatigue. It always occurs when we have to make a choice in many situations during the course of the day. Anyone who has ever planned a wedding knows this: choosing a menu, choosing wedding cakes, choosing decorations, choosing clothes, choosing music... anyone who does all this at once will soon have the feeling of being totally exhausted. This means that any self-discipline is lost and sudden eating attacks often occur. Therefore, it is better to take breaks more often during the day and treat yourself to small recovery phases in order not to reach this point in the first place.
Another tip is to exert a slight social pressure on yourself. There are studies that you can lose weight more successfully if you tell others that you are on a diet. This puts yourself under a certain amount of positive pressure and is more likely to follow the rules of sensible eating. You can even post your intentions on Facebook and increase the effect.
If you will look like Sami Gashi soon, I don't know. But it actually helps to become a little more disciplined.