Watch out for catsup.
After my brother had a heart attack a week before his 30th birthday (two others had 'waited' until they were in their late 30s) we had our teenage son checked. He wasn't 17 but, for his age group, he had high bp and high triglycerides. We went through nutritional counseling and learned the ingredient we needed to look for was high fructose corn syrup, a major ingredient in many foods, especially catsup. (There are a couple of name brand catsups that offer organic versions that don't have that ingredient.) Poor kid had to cut out all sports/energy drinks which is the lifeblood of teenagers these days.
The other thing we were told was to watch out for are foods that list themselves as "Zero grams transfats" because, by law, they can actually have up to .5 grams of transfats per serving and still be considered Zero. Since the serving size listed is often smaller than what we actually consume, those so-called "zero transfats" add up fast.