Eating low fat means eating very little red meat or low fat mince, eating chicken which has been skinned prior to cooking, eating very little cheese or low fat cheese (which I find tastes awful), low fat yoghourts are a good replacement, drinking skimmed milk. Only fry anything in very little oil (olive or candola) and of course chips, bacon, crisps, mayonnaise, salad dressings etc are a bid NO NO!
Replacing meat with fish or eggs or even a complete meal for a vegetarian meal also helps.
As for low sugar, best thing is to avoid all sweet desserts, cakes and biscuits and replace by fruit. Baked apples and baked bananas are really nice but only natural sugar in them. Good luck to your hubby.