dog on diet

Question
About five years ago, we adopted a dog from a local pet shelter.  He's the best behaved dog, no bad behaviors.  He can be rowdy, active and needy, but no trouble behaviors.  Our vet instructed us to put our medium sized mixed breed dog (who weighed in at 51lbs.)on a diet.  They suggested no more than 3 cups of food a day, and to consider giving him some veggies as one of those cups.  We've stuck to this diet religously since the visit.  Our dog has now develped some odd behaviors, that he's not displayed in the past.  He gets into our garbage, both bathroom and kitchen, daily, he is now attempting to eat off the kitchen table and coffee tables, he is constantly searching for food.  These are all things he has NEVER done prior to this diet.  Is he not getting enough to eat?  When it first started, I assumed he needed to adjust to the new food levels.  But, he's been on this diet for over 8 months now.  Our cat was also placed on a diet, and she's fine.  Do I need to get back in touch with the vet, or increase his food, or do something different?  He doesn't look malnurished.  You can't see the ribs, his coat is shiny and healthy, nose is wet, he drinks and bathroom habits are normal.  In fact, there is still some fat on him.  He is not allowed in the kitchen while we eat, and he continues to obey that command, but as soon as we leave that room or the house, the scavenging begins.  What do I do?

Answer
Hi Holly!  It does sound as though he is behaving in this way because he is hungry.  I would get in touch with your veterinarian and let him know how your dog is handling the new diet.  I would also recommend having him checked for Hypothyroidism, as these are common behaviors with this disease.  Hypothyroidism can be treated with regular medication and is quite common, so don't panic!  I would also suggest giving him healthy treats between meals, like apple slices or baby carrots to keep him from trying to sneak snacks.  Increasing his activity level may also help this situation.  More walks and play time can decrease appetite.
Have you ever heard of Kongs?  Kongs are round, unbreakable toys that you can stuff with your dog's favorite treats.  If you have one or are willing to get one, I can recommend this:  To plug up the Kong, stuff some of his regular food in one end.  Then stuff the Kong with non-fat yogurt (this is excellent to control yeast in a dog's ears and will not cause a weight gain) along with some small apple pieces.  Plug up the other end with just a bit of peanut butter.  Put this in the freezer.  During the times that your dog becomes a scavenger for food, give him the Kong.  It will be stuffed with very healthy foods for him, and the freezing will keep him occupied with it until all the contents are gone, therefore, by the time he is finished with the Kong, he will be satisfied.
I hope this helps and please, if you have time, let me know how he does!
Give him some kisses for me,
Hilary