I got the nuts thing wrong. Brazil nuts are high in fat and contain an immune boosting substance. But it's Pecan's that are one of the highest calorie foods. I wouldn't eat too many of those yourself though. I snacked a bit too much on pecans once and a routine blood test showed I had a high level of something that could have meant cancer of the parathryoid - or it could have been caused by eating too many pecan nuts - it was the latter of course! I was eating them to stop me eating sweet stuff!
One a week for a hamster is fine though
Plus a different nut in between.