After I had my second child, I lost most of the pregnancy weight pretty quickly. I was active throughout the nine months and started back into my regular routine soon after birth. I even started training for another marathon when my son was 7 months old. But I had this pesky 5-10 pounds that just wouldn't go away. I assumed it was just because I was nursing, but I stopped when my son turned one and those pounds still hung on. I couldn't understand it; I was extremely active and ate a (generally) healthy diet. Was I destined to keep those extra pounds forever?

Even though I heard it all the time (from myself and other members) on the SparkPeople Message Boards, I never thought this advice applied to me: "You can't out-train a bad diet." In general, I eat 4-5 servings of fruits and vegetables a day, whole grains, and try to follow the principles of a healthy diet. But I was also eating a small handful of M&M's here-and-there throughout the day, I could easily go through a box of Nilla wafers (one of my favorites) in a couple of days, and I'd bring home cookies or some other kind of treat far too often. I always felt like it was my reward for a hard run or a really good workout. I was sure I was burning tons of calories, so I should be able to eat a few extra, right? In reality, it wasn't just a few extra, it was many extra. And those treats were the reason I couldn't lose the last of the weight.

A new survey from the Centers for Disease Control and Prevention reports that obesity rates remain around 28%, which is the same as the data from 2008. The good news is that in 2009, 34.7% of Americans claimed they engage in regular leisure physical activity, up from 31.9% in 2008. If people are more active, why aren't less of us obese? There could be a number of reasons, but one of my guesses is that even though we're moving more, we're still eating too much.

Once I started being very conscious of my diet and cutting out a lot of the extra sugar, I lost those last few pounds pretty easily. My diet is far from perfect, and I still enjoy the foods I love. I just try to eat them in moderation. For example, I'll measure out one serving of Nilla wafers instead of eating half of the box in one sitting. And I try not to use food as my reward for a good workout. My reward is the feeling of accomplishment I have after I know I've pushed myself and met the challenge.

Have you ever used exercise as an excuse to eat more than you should? In your experience, how important is diet versus exercise when it comes to weight loss?