I have been using semi-skimmed milk and low/no fat yoghurt; as I assumed the lower fat would be better for me. Do I understand correctly, from Session 2, that I should switch back to unskimmed milk and standard yoghurt (i.e. not a reduced fat variety) as that is better for me, in terms of managing diabetes?
It mostly depends on which dietary approach you are following. If you have decided that a low fat approach is better aligned with your needs and preferences then the reduced fat varieties may still be a more suitable option, though when it comes to yoghurt it is important to make sure there has not been a lot of sugar added to replace the texture and flavour that is lost when the fat is removed.
If you think a Mediterranean or low carb dietary approach are a better fit for you though then there is no reason to avoid full-fat yoghurt or whole milk. The available research suggests that the consumption of full fat dairy is related to improved health outcomes, or at least no worsening of outcomes, so if you prefer it then it can be a suitable option.
The key message is that we do not need to fear foods because of their fat content if they are nutritionally dense foods that have not been highly processed. The amount of these foods that you include will vary depending on which dietary approach you opt for.
Personal preference will play a part in this too, as adopting a dietary approach that you enjoy enough to stick to is important if you are going to see long-term benefits. So if you prefer the taste and texture of full fat options this might help you decide which approach you'd like to experiment with.