I think a daily portion of this, that and the other is probably safe. But the cumulative effect on our gut flora and probably other physiological processes is often, in my amateur but interested opinion, is to gradually mess them up.
Eg coffee stimulates the adrenal glands - no surprise there - this causes blood sugar to spike. Repeated spikes and the subsequent falls in blood sugar are known to be harmful.
It's my understanding that some of the sugar substitutes such as glucose-fructose syrup and I think aspartame are metabolised in a different way from the fructose which naturally occurs in fruits and doesn't contain the fibre from the original plant which helps to slow down the release of sugar into the bloodstream and is necessary for good gut health.
And so on and so on with gum, emulsifiers, foods containing sodium nitrites. I think that whereas in the past it was fine to focus on getting a good balance of protein, fat, carbs and fruit and veg (I do know that fruit and veg are a source of carbs) a lot of our food is now so different from its original form that it's really easy to unwittingly take in a lot of nasties with our protein, fat and carbs.
We tend to not eat enough fibre either as our carbs are so refined - white pasta anyone? 50/50 bread, brown bread; malted bread; they look healthier than white but mostly aren't wholemeal. Not to mention the emulsifiers or the enzymes added to speed up the action of the yeast, reducing the amount of beneficial goodies in the process. My impression is that a 'modern' ham sandwich isn't very healthy at all. 