@Rodcat As I understand it, fats don't really help in preventing muscle loss. You need to eat a few complex carbs (foods that are broken down to release glucose more slowly so don't cause blood sugar spikes) rather than simple carbs (things that break down quickly into sugars and do cause blood sugar spikes). Complex carbs are things like root vegetables, legumes, pulses - see the article here
Discover all about complex carbohydrates, including the truth about carbs and weight control & 5 foods naturally rich in complex carbohydrates
www.avogel.co.uk
Obviously the best thing for each person to eat varies so maybe find a registered nutritionist or clinical nutritionist to advise you (or get a referral to one) because carbohydrates are complicated!