Things to be concerned with in relative order of importance.
- Preservatives; such as sodium benzoate.
- Artificial sweeteners; such as Splenda (sucralose), Sweet'N Low (saccharin), Equal and NutraSweet (aspartame), acesulfame, neotame, and even Stevia.
- Food coloring.
- MSG.
- High levels of sugar; such as HFCS.
- Salt content combined with level of exertion.
Preservatives, MSG, artificial sweeteners, and food coloring all have the possibility of causing cancer over time.
Google.com -
food preservatives cancer
Google.com -
artificial sweeteners
Google.com -
msg cancer (not proven)
Google.com -
food coloring cancer
Artificial sweeteners also have the potential of causing weight gain.
Google -
artificial sweeteners causing weight gain
Consuming high levels of sugar habitually before a meal or combined with long term poor nutrition may cause diabetes. So long as a person eats healthy and consumes the sugar after the food (like desert), a physically active person will be fine. Slip in any of these factors over the long term introduces the possibility of developing diabetes: sugar consumption before eating a good meal, proper nutrition, or (inclusive) physical activity.
Edit:
Personally, I drink neither soda nor gatorade, and stick mainly to tea, milk, water, and juice. Maybe once or twice a year I will drink soda. I have found that a proper diet removes the need for the extra sugar found in soda. Also, I do not consume anything with preservatives, artificial sweeteners, or artificial food coloring. IMO, soda is better than gatorade.
However, we go through cycles in life. For a few years we may prefer soda. Then our tastes change and we drink gatorade. Then we later decide to go pure with tea and water. This is life. I drank mostly soda through my childhood and stopped drinking soda around 22 like your son when I also stopped eating fast food. It is possible consuming in these cycles may prove no danger for short periods of time (let's say < 10 years) relative to the length of our life.