You may be gaining weight not because you are a glutton but because you may have some underlying health condition. Sometimes you may experience unexplained weight gain which is also very difficult to get rid of. You can exercise and diet as much as you want. But this will hardly have any effect on your waist size. Your weight scale will still tip too much to the right. One reason for this may be inflammation. So to achieve long-term weight loss you need to first figure out if inflammation is behind your weight gain. Consult your doctor and he can