Gyms are oversold to people trying to lose weight. First, weight loss is mostly an eating issue. Also, the social anxiety involved with going to the gym can be intense for many out-of-shape (and even in-shape) people. There are so many other ways to exercise than going to the gym! Some people do great exercising at home with the right machine or equipment, but it can be difficult to motivate yourself to use it often enough, intensely enough, for long enough. Walking is incredibly underrated, and gets people outside. Even better is walking a dog. Don't have a dog? Adopt one. Then you'll be outside, walking (every day, at least once), and probably getting a lot of very positive attention. This can be great emotionally as well as physically. I can't recommend dog-walking enough to people trying to lose weight.

People should do whatever works for them, but the standard "diet and hit the gym" advice is extremely narrow-minded. A lot of the time, overweight people just aren't preparing their own meals often enough. You don't need to starve yourself to lose weight. No one who's at a healthy weight is starving, and you can still accommodate an occasional burger and fries, a pizza, chicken wings - whatever indulgence makes you really happy.

Little steps lead to big progress. Preparing your own meals, not eating unless you're hungry, and finding a form of exercise that you can do every day goes a long way!