Remember, at some point common sense should prevail: every pound of lean muscle burns 15 calories per day, every day, just being there. By far the easiest way to get leaner is to increase your calories, and your lean muscle mass, which will INCREASE YOUR BASE METABOLIC RATE AS YOU GROW OLDER. ONLY resistance exercise can do this. And added benefits are stronger bones, and higher androgen levels.
It's called "fueling the furnace". Endless hours of abs, and cardio, are not only futile, but, they train your body, over time, on how to become a fat-storing machine. That why fat folks so often fail. They don't do their homework and want to be spoon fed, and get their diets "upside down." The mindless cardio training causes what's called a feast/famine response, and slows your overall metabolism (because of caloric deficit).
The more muscle you carry, and provided you have adequate calories, and metabolic activation (intervals are by far the best), you'll get leaner, stronger, and raise your metabolism, as YOU GROW OLDER, particularly if androgen levels are properly maintained.
I might also add that intervals, unlike mindless cardio, increase your cardiac threshold as well as cardiac endurance. (They push the window every time if you do them right. That's why I can be 47 at 10% and run my heart rate at 160 BPM for 20.)
Let common sense prevail; do your research into the human machine. Do NOT be caloricly restrictive. No point in doing mindless hours of abs if you don't have leanness.