To begin, it is important to recognize the importance of the side effects of weight loss. Many people, when starting, state that they would like to reach subjective goals like "looser fitting clothes" or "being able to keep up with their kids," but for true success to be tracked, we'll need something empirical and tangible.
Enter BMI, body fat percentage, measurements, and the scale.
By having hard numbers to work with, it's possible to track all of the metrics of having a healthy weight. While BMI is arguably an unfair method of measurement of health, since it can't account accurately for muscle mass adding to overall body weight, most people with a desire for weight loss don't fall into the "body builder" category. For those of us who desire losing weight and not training to be professional athletes, we can start here:
Hard measurements will never lie and allow for honest, direct tracking. Looking in the mirror gives a false illusion that can be helped or hindered by lighting, compliments from friends and family can be forced or inaccurate, and clothes can just be plain stretched out. Knowing your weight and measurements is how we'll want to start. Next, we'll want to calculate our staring point for BMI, body fat percentage, and dimensions.
With those starting points, we can see where we need to go next. These charts and more information are available at the National Heart, Lung, and Blood Institute:
Body Fat Percentages
With this beginning, we know what we're working with, we know where we should be, our next step is gearing up for how to get there. 'Phase 2: Heading in the Right Direction' can help with that!