Today we have a low carb foods question and in particular a question about tubers. We ask Prof Tim Noakes about potatoes and sweet potatoes and if they fall into the category of low carb foods. Are they allowed on the LCHF diet and which one is better for you, if any?

Prof Tim Noakes: Sweet potatoes are much better because they have more fibre and less carbohydrate, but still they are pretty full of carbohydrates. One or two sweet potatoes will give you your 25g carbohydrates and for some of us that will be all you can eat. So they’re still pretty full of carbohydrates.

Potatoes are a real problem because they are just glucose. You might as well just go and buy a bag of glucose from the pharmacist and eat that, because that’s the same effect biologically. Your brain and your body doesn’t know whether you just had a bag of glucose or had a potato. The response is the same: you have a huge glucose spike in your bloodstream and a huge insulin spike. READ MORE