starting with the typical North American diet and switching to a keto diet we would ... dramatically increase the veggies in our diet
I guess that depends on what you take to be the "typical NA diet". Veggies are essentially carbs and fibre, and keto is very low carbs ... so you have to be very low veggie ... but ... but ... you need some and have to make sure they are the "right" ones.
... and change the kinds of fats we eat. I think most of us get plenty of fat now...no need to increase it much more. Still learning about keto...
Keep reading and learning about keto ... the key is that eating fat does not make you fat. In fact, eating fat is healthy and makes you burn fat. Of course, we are talking about healthy fats (avocados, nuts, cheese, butter, MCT oil, salmon, sardines, prime rib, bacon) rather than unhealthy fatty fast food ... pizza, fries, burgers, and so forth ... that people eat way too much of.