Nowadays, the percentage of people that are overweight is dramatically increasing, causing them to suffer from diseases and have a hard time trying to get back in shape. I think this is strongly connected to the lifestyles that most people led which includes fast food meals and hours spent in front of a screen.
Indeed, the prime cause of gaining weight is the diet that we decide to follow, whether we include all the fundamental nutriments or we opt for a sugar-based one, alternating between hamburgers and sweets. Secondly, people prefer to spend their free time watching shows or playing to videogame instead of going outside and have a nice and long walk. In fact, there are documentaries that show the life of extremely fat people, who are not able to walk anymore and spend entire weeks without never leaving the houses, switching from the sofa to the bed.
As far as I can say there are many possible solutions that can be found. It is clear that the main cause is an unhealthy lifestyle, which is caused by both disinformation and laziness. However, this can be improved for instance by government intervention. For example, it could be helpful to limit the consume of high-sugar foods and implement eating and health education classes in schools, where students could learn what are the consequences of a healthy lifestyle and what would happen if we do not take care of our weight and fitness. Indeed, some great improvements could be noticed both on the short and the long period.
In conclusion, I believe that forcing people that are overweight to stop eating junk foods by limiting their consume would certainly help, although the only solution to see permanent changes is by educating them to an health way of living, which includes sports and activities outside.