My husband is a diabetic and eating things that most people would consider healthy such as potatoes, bread and some grains and beans will spike his blood sugar to dangerously high levels. That is the main reason we eat more tofu and nuts than other McDougallers. I've had to adapt the diet to make it work for him, because veggies are great, but he needs something else on his dinner plate at night that won't send his blood sugar through the roof.
Nordgirl, is your husband Type I or Type II? And are his spikes in response to potatoes, bread, and beans something you've directly observed, or simply what you/he expects?
I'm curious because as a Type II, spikes in response to these foods are what I would have expected based on my experience prior to eating plant-based. But in fact, I don't experience them, unless there are oils in my diet as well. But here's the catch -- even fairly small amounts of oils (like the oils in tofu and nuts or avocaado) can sometimes be enough to "allow" (mediate? facilitate? cause?) the spikes.
My own completely unscientific "explanation" for this is that the insulin malfunction in Type II diabetics (scratch that and make it: "in me") seems to be more a function of "carbs + grease" than a function of carbs alone.
Of course if your husband is Type I, all bets are off -- that's a totally different deal. And we're not all medically identical, so I can't necessarily expect what works for me to work for somebody else. But this way of eating is still new enough to me that I remember just how world-shaking it was for me to discover that I could eat a plate of potatoes without my blood sugar spiking. So that makes me curious enough that I've got to ask whether the spikes you talk about were an observed phenomenon in the context of a consistent series of no-added-oils meals, or whether (like many Type II diabetics, including me up until a year ago) your husband might have been understandably reluctant to give carb-heavy foods a fair (greaseless) test because of having been taught for years to expect big spikes in response to them.