In this respect, for people who agree with this title, I have a bad news: sport helps you lose weight but it is not the best way to lose weight.
Several studies carried out on a considerable group of persons who have undergone an intensive sports program for about 20 weeks without having a controlled diet made these findings: Men lost enough weight, but not enough to reach the ideal weight because at a certain level the weight remained constant, no matter how much exercise they were doing. In women no significant changes in weight were noticed. We could say, therefore, that sports helps men more in the battle against excess pounds.
There is a medical explanation, namely that the body understands the increasing demand for energy through sport and, indirectly, increases the caloric need. Thus, some people eat more or have food cravings that are not important in terms of quantity, but quality, highly caloric foods: nuts, candy, chocolate, cream, etc. The calories of one chocolate are lost in 10 minutes of fast walking.
Sport does have extremely important effects when combined with a proper diet. Note however the role of sport: to increase the energy production! In conclusion, sport will maintain weight, but not diminish it, the diet takes care of the latter effect. So do not waste time only working on the elliptical exercise equipment and eat healthy while doing it to maximize your chances.
If you consume fewer calories, your metabolism will change, because the body will try to protect itself from starvation. This will greatly decrease the energy production, protecting as much as possible the deposits that are found primarily in the form of fat (fatty tissue) and less in the form of glycogen (the liver). So even if you eat less the extra pounds will not go away because they are the backup plan and no one gives up the backup plan.