I believe that you are what you eat. If you eat crap, that makes you.....you get it. With the obesity epidemic rampant in children, i find it reprehensible to set them up for a lifetime of battling being overwieght by teaching them bad habits when they are young. Junk foods are "once in a while foods" in our house. I do not use french fries or cake as a reward, because I don't believe in using food as a reward at all. I think this leads to the situation where grown people begin to find comfort in food and turn to food when they are upset, angry , depressed, etc. My family enjoys all aspects of food-gardening, harvessting, canning, freezing, etc. I love cooking and my daughter enjoys cooking with me. But she has a healthy relationship with food. When we do have desserts, they are always home-made. Store bought desserts have so much more fat, sugar, and preservatives than anything you could make at home.
As for the vegetables, if Chu likes cooked tomatoes and maybe spaghetti sauce, you can always add cooked veggies to his spaghetti sauce. If he can visually detect an unsavory vegetable in his food, try pureeing them and adding them to foods you know he will eat. If he likes muffins, add some fruits to his muffins. Cook with applesauce replacing some of the fat and egg in a given recipe. Make him fresh fruit smoothies with a little bit of a variety of fruits in additioni to the ones he really loves. You could also make him zucchini bread and carrot cake or muffins. Cook rice in vegetable broth instead of water. If he likes scrambled eggs, then try adding a little bit of pureed cauliflower to them. he won't really notice their presence, and he will be getting a little bit of them into his diet. Lastly, don't worry too much about it. You can lead a horse to water, but cannot make him drink! All we can do is give them healthy options.