I know what you mean- and you're right-- basically , by intentionally disregarding our health and eating things we know we shouldn't, we are actually causing an extended suicide. I think there are many forms of suicide.
I think , as you said, there is a suicide based on ignorance, and "ostrich in sand" self-blindness. Like pretending our health will be okay whatever lifestyle we choose to follow., Or the motive could be "you only live once, so do whatsoever your body wants", only to find out that there is a price to be paid eventually. Like a diabetic who ignores wisdom and eats all the Sugar he wants, then wonders why he has to go through amputations later in life.
Then there is the immediate suicide based on desperation and a moment of extreme personal agony, which the person finds so unbearable, that they feel death is the only way out.
There are even other forms besides these---like suicide to spite someone,etc., or suicides because the person is addicted to heroine, and feels that killing themselves will only help thier family from carrying his/her burden.
I think if placed in a certain circumstance, any one of us can be tempted towards suicide, so we really do have to be our "brother's keeper" and just try to be there emotionally for each other. And we should pray for the souls of suicide victims, that they can go towards the Light and not be stuck through self-guilt on the Earthly plane.