It may be hard to find the studies that would apply, because just adding nuts to the SAD may very well end up replacing calories from wheat, or other junky snacks. I mean if all the people now have nuts to eat for a snack, so they leave out their crackers, there's going to be some conflation.

Study Crowd sourcing. Email me if you want a paper to read:

Vrimj read Effect of moderate walnut consumption on lipid profile, arterial stiffness and platelet activation in humans. This one basically proves you have to eat more then a mouthful of nuts to get benefits, there are some sites that show strong positive results, but they were at a higher level of walnut intake.

This one has them eating 15 g (about 8 walnut halves) a day for four weeks. It didn't have a lot of change in BP (slight increase if anything) and while there were some effects on the lipid panel (lower LDL and some increase in triglycerides) but they were not significant. Other comments (quote is below) in the paper about the concern for the high amount of fat consumed with nuts at clinically significant levels were not important but did explain why someone would do a study on nuts and then not have people eat nuts in any quantity. This is the only health concern mentioned in the paper. I can only conclude these people have never seen me eat nuts.

"The large amount of walnuts consumed in many of the previous dietary intervention trials provided up to 20% of total energy and 55% of daily total fat intake. There have been concerns that this proportion of fat energy from walnuts may be too high to be practical or sustainable in a non-research setting (Feldman, 2002; Banel and Hu, 2009).)"

Jaya says: "...there is evidence that high linoleic acid diets might be really bad"

This is actually somewhat confusing. Partially hydrogenated and rancid vegetable oils (coincidentally high in O-6) clearly show negative effects in studies. Other than that, it's less about the O-6 intake, and more about the specific tissue concentrations. However, there are various factors that can influence tissue concentrations of O3 and O6 other than just dietary. I tried to touch on this in my question: If dietary and serum cholesterol aren’t always related, could the same thing be said about linoleic acid? It doesn't seem like PUFAs in refined processed vegetable oils and PUFAS in avocados, nuts, meat etc have identical fates in the body. I feel like this is one of the areas we are most clueless about.

PieterD, do a search for nuts and lectins. or for the amount of omega 6 in different nuts. it is fairly clear that we shouldn't be eating a jar of almond butter everyday.

I am not aware of direct evidence that unlimited consumption of nuts is bad, but nuts are high in linoleic acid and there is evidence that high linoleic acid diets might be really bad. It may be that fresh nuts provide their LA with enough fat-soluble antioxidants that they are not bad at all. Nobody knows this, as far as I am aware. Then, there is the !kung who eat lots of mongogo nuts. They are reasonable healthy but have poor glucose tolerance (Stephan wrote about this recently), especially for a society with a traditiional diet. Since there's no reason to go crazy with nuts, why not keep them to a reasonable quantity?

I, for example, use macadamias and cashews as one of my main sources of LA, along with pastured eggs and pork. Most other good fats (dairy, coconut, cocao) have about 2% LA and I eat lots of potatoes, so I need some relatively high LA foods from time to time to avoid LA deficiency... For that, as I stated, I use mac butter (mac + cashew) and eggs; sometimes avocados or olive oil too... I also have an occasional brazil nut for the selenium...