To not understand why health research is so contradictory?

[MissHooliesCardigan]

I can't link but the main headline today was that a large scale study has concluded that the majority of cancer is caused by lifestyle factors like smoking and diet.
This is the complete opposite to the findings of a similar study only a few months ago which concluded that the vast majority of cancer is due to 'bad luck' and not to anything that the person did.
Advice about diet seems to change every 5 minutes. For years and years, we've been told that fat is bad but that seems to be changing and it's now sugar that we need to avoid. I had Tesco sushi for lunch yesterday and the labelling said that it constituted 30% of my daily sugar intake! How can fish, vegetables and rice be full of sugar?
Fruit juice and smoothies are no longer seen as healthy because they're full of sugar.
I know there are some research findings that seem generally well established eg I can't imagine a study concluding that smoking loads of fags is good for you but can any science/research people explain why advice keeps changing and how 2 studies about cancer carried out at around the same time can produce directly opposing conclusions? No wonder nobody knows what to believe.

Sushi (even proper stuff) rice has a dressing with salt and sugar added to it, so that won't be helping.

Science can be a lot that old parable of the elephant. You blindfold 5 people and get them to feel the elephant and everyone feels a different bit and comes to a different conclusion. They are all right, but not completely right (and some seemingly contradictory)

That is the problem with extremely complicated systems which all interconnect with each other (which we don't fully understand) and different people discovering different pieces of the puzzle at a time.

I think it's probably fair to say that the findings of all these studies have some truth in them (even seemingly contradictory ones) but are not necessarily the whole picture

It's basic economics. If you are a company producing coffee, you are going to keep funding research which shows that coffee is good for you, and make sure that press releases are sent out regularly to gullible journos to say that coffee is good for you. That is the way our world works.

Telling people how to live healthy lives makes money for nobody. Not least because it's very simple.

Sorry haven't read the thread, but I think once again this has been very badly reported just to get a "good" headline. The research also included environmental factors and as far as I can see that could include a multitude of things that are nothing to do with a bad lifestyle or make it the fault of the person with cancer.

A little bit of everything does you good and everything in moderation (except smoking of course). Can't go far wrong with that.