A lot of people don't seem to grasp the difference between losing weight and burning fat. Those who want to lose weight aim to see a certain number on the scale. If you are one of them, you need to learn the difference, or your 6 pack quest is doomed to failure. You need a different goal.
It's easy to see why many people make this fundamental mistake. They think about when they were young and fit and sexy, and remember that they weighed 110, 130, 150, 170, or whatever the number was. Then they figure if they looked so hot at that weight, all they'll need to do is lose a few more pounds and soon they'll be sporting 6 pack abs and look like a fitness model. But it doesn't work that way.
To a large extent, the number you see on the scale is meaningless. It doesn't much matter what you weigh. The number on the scale tells you nothing about what really matters if you're trying for that 6 pack. To eliminate your gut and get a body like a fitness model, you need to burn fat, not lose weight.
As we age, our bodies tend to lose muscle mass. Typically, a person can lose 5-10 pounds of muscle every 10 years after the age of 25 or so. If you're losing muscle, but maintaining your weight, you are adding fat. So for most people, even maintaining the same weight you had a decade ago means you are losing ground. You're body is gaining fat and losing muscle, even if your weight isn't changing.
Even worse, your metabolism slows as you lose muscle mass. So it takes less and less food to maintain your weight, making it that much harder to even keep that number on the scale steady, much less actually build the body you want. Theres little hope for your quest.
Clearly, you need to take a different approach to this problem. Your goal should be to burn fat, rather than lose weight. Why? When you look at people with 6 pack abs, you're looking at someone who has a very low amount of body fat. No matter how much they work out, no matter how fit they are, you're not going to see their abs unless they have got their body fat levels very low.
The way they do this is by working out very hard, not by dieting. The leanest people out there all exercise very hard. They work out long enough and hard enough to force their bodies to draw on fat reserves for fuel. They literally burn fat for fuel, pulling it out of the bodies storage areas and use it to power their workouts.
And here's an added bonus. The kinds of workouts that do this best (think sprinting and weight lifting) also force your body to rebuild your muscles bigger and stronger to handle the stress. And that takes energy, which means their bodies burn fat to do the work even after the workout is over.
And there's yet another bonus. The extra muscle your body builds to handle the stress of hard workouts requires extra calories to maintain itself. So your body burns more calories during the day, which helps burn fat.
Which brings us to the final reason why burning fat rather than losing weight should be your goal. If you do this right, you'll be adding significant amounts of muscle mass while simultaneously reducing the amount of fat you carry around with you. You might lose weight, you might stay the same, you might even gain weight on the way to that 6 pack. The number on the scale says nothing about the fitness of your body or what you see in the mirror when you take off your shirt.
So now you know another secret of success on your 6 pack quest. Focus on burning fat, not losing weight to develop your best body.