First of all, what makes you think he is overweight? It's actually not that common for such a young dog to be already overweight, though it does happen. Do you say this because he weighs twice as much as you thought he would, or does he actually have a lot of excess fat so that he has no waistline and you can't feel his ribs through the fat? If it's the first one, sorry, you got a bit-little dog. Only if it's the second one should you make him try to lose weight. If this is the case, just reduce his food and try giving him veggies as treats (green beans or banana) instead of those bacon-y things most dogs get. A treat here and there is fine, but my vet says every time a dog has a treat it's like a human having a Snickers bar-it adds up. Make sure he gets lots of exercise every day. I know the raw or homemade diet is a huge trend right now-I would actually advise against it unless you are very knowledgeable in the requirement's of a dog's diet and have a scale at home to weigh your ingredients. All reputable brands of dog food already have all the essential nutrition for a dog, and I know dogs who have gotten preventable diseases like osteoporosis because their owners attempted to feed them raw/homemade. Not to mention parasites or bacteria found in uncooked meat. Also, please don't make your dog lose weight fast. A little bit at a time is perfectly fine! Don't starve him or he can get sick, especially since he's coming out of puppyhood and they can't regulate their blood sugar levels as well as adults. If you have further questions please see a vet and they can help you-he might even have underlying health issues that make him overweight. Good luck.