Interesting you should bring this up as I have recently done some testing.
I used to eat eggs and meat every breakfast. Then one time I ran out of breakfast meat so I had oatmeal and eggs instead. Later that day my website finally appeared on the first page of Google. I was happy, but didn’t make the connection at that time.
I made it to the grocers, had my usual breakfast the next day, and woe, my site fell off the first page 
On a hunch, I skipped the meat the next day, and lo and behold, back on the first page ! 
Much elated to have discovered a great SEO secret I experimented further. I found that if I also eliminated eggs, the site came up not only on the first page, but within the top 3 results 
I have checked with a few others, and sure enough, those that have both meatless and eggless breakfasts consistently ranked tops in Google search.
NOTE I have not looked into how this affects other search engines. It may very well be that it causes better results only for Google and worse results for all the rest.