Too often in life, I see people seeking, or selling, a "magic bullet".
They seek, or offer, a "one shot" solution to a problem.
The real problem is that most problems, other than immediate ones of the moment, have multiple causes and interactors. While one choice may have an impact on a small portion of what is actually causing, or increasing, the problem, solving the problem usually takes multiple choices and changes.
Yes, you, and I, may be putting on extra pounds 'because' we are eating too much ice cream, but, we are eating too much ice cream too often, we are sitting too much during each day, we are getting older, we have the genetic makeup passed to us from our parents and ancestors....the list of reasons goes on.
It's not JUST eating too much ice cream.
We are not poor because of one thing. We are not sad because of one thing. We are not homeless, heartless, or hopeless because of one thing. We have to look at, and make choices about, a multitude of things to become, or at least move closer to becoming, whatever it is we hope to be.