Candy and soda aren't great as they will create peaks and troughs of energy - the odd hamburger or hot dog isn't going to do any harm as long as it is not a staple of his diet.
Pasta is fine, wholemeal is better in terms of energy release. Wild rice is also good. Potatoes are good. For variety you can try sweet potatoes. Generally try and avoid things that come in crinkly packages - that's my general rule - but it isn't scientific!
Oats/porridge is a good option. I personally love porridge with roasted nuts (almonds/hazelnuts), raspberries and blueberries with a soupcon of maple syrup (I don't like things that sweet).
Main courses, wild rice, potatoes, wholemeal pasta that sort of thing with chicken or any other protein is a good mix. Though don't forget your fats - good fats such as nuts, avocado, olive oil, oily fish etc... these are also very important. Whilst less good for endurance as creating energy from fat is a more complex process, it is also helpful for fuelling the body, but also for good health.
Snacks are easy, oat cakes, nuts, bananas a mixture of all of those and more are great for grazing on.
It doesn't have to be too prescriptive, I personally do not have a sweet tooth and I can live without junk food (though I do love burgers - they are my treat when I have my cheat meals) - it does not mean you HAVE to live without them, just be moderate in your intake.
