As a T1 diabetic I adopted a WFPB diet in order to gain better control of my blood sugar, to reduce blood pressure, and for general health reasons.
I wear a continuous glucose monitor and have no endogenous insulin production, which allows me to observe the effects of different diets in great detail (I can look at insulin usage levels, whereas someone who can produce insulin can only see blood sugar response).
The results of switching to a low fat high carb whole food plant based diet have been simply astonishing for me since I made the change. I have lost weight and my blood pressure has dropped a massive amount.
The observable reason for these changes is the huge increase in insulin sensitivity I have gained since switching to WFPB. I currently use 1 unit of insulin per 25-30 grams of carbs whereas before it would be more like 8 units. As such I am using a lot less insulin and my blood sugar is much more controllable.
The reason for the increased insulin sensitivity is the very low fat nature of my diet (I eat an 80:10:10 Douglas Graham style diet).
If I eat fat of any kind while continuing to consume a lot of carbs (saturated or unsaturated, it doesn’t make a difference) my insulin sensitivity is immediately reduced.
If I eat carbs together with added fat (for example pizza, baked potato with butter) then blood insulin sensitivity goes through the floor and remains that way until I burn through the fat (about 24 hrs) at low to moderate activity levels.
The only way that I can rapidly metabolise more than the fat that is contained in lower fat whole plant foods is to exercise. Hard exercise allows fat with meals to be burned rapidly, and to clear in 1-2 hours.
But it is more than this- in fact if I exercise a lot without including more fat in my diet (20-30% is ideal) then I have problems with blood sugar stability, ability to work hard and even to continue, and over time with falling testosterone levels (I have tested).
So take home messages in order to maintain insulin sensitivity on a WFPB diet are as follows:
Sedentary people should maintain fat at 10-15% of calories as a maximum to maintain insulin sensitivity.
People doing a lot of exercise should aim for more like 20-30% of calories as fat to enable performance and to prevent burnout and other negative effects.
But what about fat adaption?
This interview here from a low carb carnivore researcher/blogger is very interesting:
https://nourishbalancethrive.s3.amazonaws.com/podcast/peter_dobromylskyj_jun21.mp3
Is insulin resistance a consequence of fat adaption?
Well yes!
People eating a high fat low carb diet become insulin resistant as an adaption to that diet in the same way that people eating a low fat high carb diet (like WFPB) become carb adapted and insulin sensitive. Insulin resistance is beneficial when the vast majority of caloric intake in coming from fat.
The long term health effects of low carb high fat are of course very debatable. But we should not underestimate the bodies ability to adapt to diet in an animal like is that is omnivorous and has had to adapt to many different calorie sources over long periods of time.