Hi Tea!
The Guidelines are talking about all kinds of exercise, not just aerobic.
The
2005 Dietary Guidelines for Americans recommend a minimum of 30 minutes of moderate intensity exercise "on most days" to reduce the risk of chronic disease. So that recommendation is for everyone, for general health benefits. Next it recommends 60 minutes of moderate to vigorous exercise on most days to "to help manage body weight and prevent gradual, unhealthy body weight gain in adulthood". Finally, in order to maintain a weight loss, it recommends "60 to 90 minutes of daily moderate-intensity physical activity while not exceeding caloric intake requirements".
You can see that the highest level of exercise recommended is to maintain a weight loss, not for losing weight. As an almost seven-year maintainer, it's not surprising to me that most people would need to exercise more to keep the weight off. I think it takes into account the challenges of maintenance and the fact that studies have shown that exercise is by far the biggest predictor of maintenance success. We've frequently talked about exercise in the Maintainers Forum and it seems that many of us meet this guideline of 60 - 90 minutes of exercise. I average about 90 minutes a day myself.
As for what you should do -- as always, you should do what works for YOU! These are guidelines, not rules chiseled in stone. If what you're doing now is working for you in your weight loss phase, there's no reason to change.