Coffee can help you lose weight.
The reason that coffee can help you lose weight is because the coffee helps reduce your appetite and when your appetite is suppressed and reduced you eat less.
And by eating less you lose weight.
The more you eat the more you may gain weight.
However some people including myself can eat a lot of food and still not gain much weight or any weight at all.
But coffee does help in weight loss.
You still need to exercise, eat healthy etc and then you will lose weight.