I have to do the plant fats in moderation, like very very little. I do 2 ounces
2x a day. So I'll have a tablespoon or so of walnuts with my breakfast beans and oats, and I'll use 2 ounces
of avocado or guacamole mixed with salsa as a salad dressing. I have to go easy on it because they are so calorie dense.
Jeff Novick has a good DVD on fats v. oils and how much we need. All plant foods contain some fat, enough to enhance vitamin uptake, at least that is what the plant based doctors say. There's no need to add any, but to boost omega-3 I do the bare minimum.
The other thing a plant based (whole foods) diet does is provide the correct ratio of o6 to o3. I can't remember the ratio but Novick reported that if all you eat is veggies, fruits, beans, and grains, o6/o3 will be taken care of in correct ratios.
I have heart disease and hypertension in my family so I have to stay away from animals and oils. I can't go near them!
ETA: There might be a YouTube on this, try "Jeff Novick fats and oils" or any Jeff Novick video on calorie density - he's pretty much the guy I follow except for down-serving on grains, I follow Bright Lines Eating.