Do you want your abdominal muscles to be clearly defined? That's certainly possible (for anyone) and it involves changing your expectations of taste and purpose behind eating. My philosophy of eating is that it's for maintenance of the mind and the body. And I firmly believe that pleasure must always be paid for (not talking about money). If you want to drink soda and eat good tasting foods, then you pay for it with possible distension of the stomach and lower energy levels. It always feels good to eat good tasting food, but you might not look very good or be capable of walking up a flight of stairs.
I have found it very beneficial to change my way of thinking. The purpose of food is to make the body look good, the mind feel good, and to provide high energy levels long after the food has been ingested. This can be accomplished by going through pain in the eating process, by eating foods that are not very satisfying. The healthier your meal is, the less fun and interesting it will be, but the benefits to your appearance and energy levels are well worth it.
As a general rule, never drink anything marketed as an "energy drink". They typically have bloated levels of B-vitamins, which simply turn your urine very yellow. You get to piss your money away, as well as get as much sugar (or more) than soda. Rather, eat 3 or 4 hard-boiled eggs. It takes more time to eat and prepare them, nor do they taste very good, but the energy they provide is far superior to any soft drinks, coffee, 5-hour energy, etc.
You should look for foods that are high in fat and protein, such as almonds, yogurt, milk, eggs. Carbs should come primarily from vegetables, fruits and wheat bread. Fat does not make you fat. It's unfortunate that a healthy energy source (fat) has the same name as the excess weight we carry (fat). They are different and easily confused. Simple carbohydrates should terrify you, such as soda, candy, ice cream.
In summary, I avoid high fructose corn syrup because I like to have a six-pack and I like to be able to not get tired at my job. I see people in their early twenties that are horribly out of shape. I should not be running circles around people 10 years younger than myself, but I can easily do that.