Sorry to add to your confusion but ,I think that you should take advice on diet from your husbands heart specialists and think very carefully before adopting a diet high in saturated animal fats.
Whereas a low carb, high fat diet may help him loose weight in the short term (and hence improve his glycemia) it may not be the best diet in the long term. Also by following such a diet e may also reduce his intake of foods that may be protective against CVD.
It is in my opinion simply untrue to say that there is no evidence behind 'healthy' eating advice. Because It is difficult to design any form of dietary research in a way which avoids one problem or another nearly all studies will be capable of being challenged.
If you want to read a summary of the research on which British guidelines are based :
The Dietetic guidelines on food and nutrition in the secondary prevention of cardiovascular disease – evidence from systematic reviews of randomized controlled trials (second update, January 2006 )
http://www3.interscience.wiley.com/journal/118554000/abstract
CONCLUSION: There remains good evidence that reducing saturated fat reduces morbidity in patients with CVD. This advice is consistent for most manifestations of CVD, with the addition of Mediterranean dietary advice and increased omega 3 fats for those who have had a myocardial infarction.
An alternative to a low carb diet is to make use of the glycemic index . . you still won't have much use for the sugar, but it may be that small portions of wholemeal pasta may be OK . A low gi diet works well for many people with type 2 diabetes. Such a diet includes less refined carbs and advocates (as with the CVD diet) replacing saturated fats of animal origin with unsaturates from fish and vegetables.
http://www.glycemicindex.com/
You might like to look at the non low carb success thread. the forum is still in its infancy (because of the history of this website) but there are sucess stories from people who haven't adopted a low carb approach. There are some similar stories in the Our Journeys thread.