Also, it is substantially more likely that your problem is far more related to lack of exercise than 'poor' nutrition. In the first place, a lot of 'bad' nutrition isn't actually bad, but the entire scientific community agrees that exercise plays a big role in just about every single aspect of health.

The problem with health and science is that science is a process of controlled studies, yet with health issues it's extremely hard to apply the same amount of controls as we can in other sciences like chemistry. This means that the gathering of knowledge is vastly slower and inferior to other sciences. At this point in the research, though, it is widely believed that the most important factor in possibly all areas of health other than severe malnutrition is exercise. Even things like brain aging. Neurologists and related scientists don't agree on much when it comes to preventing brain aging, yet they all agree that exercise is very important.