Hi.
I have fibromyalgia and stenosis, so I do very little exercise - in fact I spend a lot of my life in bed. But going low carb really had a dramatic impact on my blood sugars and weight.
You say you are still eating rice and potato - both of which have far too many carbs for me to tolerate. I think that very few people can do low carb to control blood sugar and still eat rice or potato.
I dropped potato, rice, breakfast cereals, pasta and ordinary bread along with most fruit.
At first I tested before and after every meal to check how many carbs I could have and which foods spiked me. For example, for me the same amount of carbs in strawberries caused a bigger spike than raspberries.
I was lucky as I started low carb straight away so my blood sugars dropped quickly. I had to go down to 85g a day and no more than 30g in one meal - but others need to go much lower.
On a typical day I have a cereal that is mostly milled flaxseed and chia seeds, with a little coconut milk and cinnamon, served with double cream - that plus a half milk coffee is about 20g of carbs.
I often skip lunch - just having a second coffee, or will have protein and lettuce/cucumber. I might have a ham or cheese sandwich using 90 second bread made with ground almonds and milled flaxseed.
For dinner I have chicken or fish, cooked with lemon juice or curry powder or herbs, and loads of green veg plus cauliflower rice.
Dessert is full fat greek yogurt and a few raspberries, or a rhubarb crumble using ground almonds instead of flour served with double cream. Sometimes I make a low carb mug cake instead.
Bedtime treat is a couple of no added sugar chocolates or some 85% dark choc and a mug of cocoa made half milk, a dash of cream and sweetener.