Breathing is something you just do, no thought involved right? A lack of movement variability (prolonged desk sitting, sedentary lifestyle, etc.) leads to altered breathing patterns that affect the amount of oxygen you receive and thus your health.
To regain diaphragmatic breathing without restraint it takes practice and exercise. The diaphragm, after all, is a muscle.

Believe it or not what you've been told about food is wrong. Most of it is fueled by lobbying groups. When the commercial dairy farmers needed more revenue the public received the 'got milk?' campaign. When wheat farmers needed a boost the public got the 'breakfast is the most important meal of the day' run. So on and so forth most of what has been touted and supported through research has been biased with an agenda (no one wants to pay for research that deems their product unhealthy).
Then the super-foods started rolling out.