There is a lack of robust observational studies comparing high-vegetable and low-vegetable populations.

“In fact, if you look at many of the studies like this, it's pretty hard to find studies that increase vegetables alone, but and it's even harder to find studies in which increasing the vegetables alone is beneficial for humans. There are some studies and perhaps in a future podcast I can go through a large meta-analysis of all the studies from a few years ago when the meta-analysis was published that were done with fruits and vegetables looking at their benefits or no change and looking at inflammatory markers in humans. Many of the studies that show benefits, they don't all show benefits for fruit or vegetables. They're sort of mixed results. The trend is toward benefit in fruits. There's not a ton of studies that are interventional with vegetables alone and even the ones that there are don't show a clear benefit.”

“Interventional studies many of them combine fruits and vegetables the ones that are just using vegetables don't always show a benefit many of the studies combining fruits and vegetables don't show a benefit”