It looks like they may have cherry-picked results from other studies to get the correlations between obesity and cancer.
The analysis of 144 published studies incorporating some 282,000 men and women also showed that gender can make a difference in the relationship between obesity and some cancers, the researchers reported in the Lancet medical journal.
I'll bet you could look at those 144 studies and come up with an entirely different result, just by using different endpoints (in other words, what do you want the results to be? Look for the data that gives you that result).
For men, the risk of thyroid cancer rose by a third and went up 24 percent for colon and kidney cancers, the researchers said. In women who went from normal to overweight, the risk of gall bladder cancer rose 59 percent and kidney cancer went up 34 percent.
"Increased BMI is associated with increased risk of common and less common malignancies," the researchers wrote. "For some cancer types, associations differed between sexes and populations of different ethnic origins."
And what fucking good does it do us to know this? Like we can change our weight with a wave of that magic wand there?
There were also strong differences between men and women for cancers like bowel and kidney cancers. Knowing this kind of information could help scientists focus research on what is exactly causing some of these cancers, Renehan said.
So correlation is not causation, right? And you don't know what exactly is causing these cancers? But I thought you said it's linked to being fat? Which is it, asstards? You know, or you think you know? Did you go into this with the idea that being fat increases risks/incidences of cancer and then looked for the data that would show that? Did you look at all those studies and control for all the things that can cause cancer besides fat? Admit it, researchers, you can do all the studies you want, and you still aren't going to know for sure what causes cancer in any particular person.
The only thing you can be sure of is that we're all going to die and you can't do a fucking thing about it. Get off the obesity-causes-everything bandwagon and look for the real causes so you can look for cures. Because you aren't going to find a cure for obesity (it's not nice to fool with Mother Nature).
ETA: Sandy at Junkfood Science has a good take on this whole mess here. Check it out.