There is cardio vascular disease in my family down some generations. When I was diagnosed with diabetes, I had all the markers heading towards that direction, they where highly elevated. I did develop gestational diabetes, I was inform what I should eat. Nothing outside that, they didn't inform about diabetes at all, never informed what my A1c was at that time.
I did tons of independent research. This did not include studies of different diets.
My research was right down to what the whole body needed to function, down to the smallest detail. Talk about in-depth research. This empowered me to accumulate forp my own ideahow to tackle my diabetes.
I found this website, which verified my thoughts, which was High fat low carb. This helped me decide to completely Change my diet, taking into consideration o family medical history.
I used myself as a guinea pig, my first HBA1c test was my baseline. Against the advise of my doctor and diabetes nurse, I bought a meter and went high fat and low carb. My next tests was 3 months later.
My HbA1c and full blood profile was done again. Everything was normal. My A1c has reduced even further after 6 years.
The only thing I have to put up and deal with, is high blood pressure which I have had for years, totally unrelated to my diabetes. It doesn't what i do, i will never reduce it.
I have found that many of these studies are corrupt and flawed. Anyone can claim all sorts. Many of them can be dismissed.
Sorry about the long post.