I don't doubt that eating healthy, and therein reducing unhealthy (junk) food does make a difference and help certain things. But I'm just wondering if it makes a big enough, or noticeable, 'worthwhile' difference/improvement. (I'll explain what I really mean by 'worthwhile')

My main concern is my brain and mental health/function, my cognitive function, memory, focus, thinking ability etc. So I do undoubtedly notice that things like, or at least, sugar in a short time period does affect them. I feel more 'spaced out', unfocused, muggy etc. for the hours after I eat it.

So I'm fairly confident that sugar would definitely be 'worth' reducing or just flat out cutting out - but I just don't know if it would make a recognizable lasting (long term) difference, like how it does short term.

And what I mean when I say 'worthwhile' is really just that eating (not necessarily just unhealthy bad junk food) is something I enjoy, it's a 'distraction', something to do, I don't know, it really seems like these are just bad excuses and they probably are, but I'm just not sure if starting and sticking to a long term (lifestyle) of eating less and healthier is really going to make the difference/improvement I would like, and if I might as well just keep eating what/how I do.

Note: I don't have like a serious eating disorder, or am severely overweight or eat constantly 24/7 or anything like that. I just don't have a - consistently - healthy diet.