If everyone has a similar amount of weight to lose, judging the competition based on pounds lost is an easy way to compare efforts. Simply measure each individual's starting weight, then measure again each week. At the end of the contest, whoever has lost the most pounds wins the competition. While this method is certainly the easiest, the disadvantage is that it doesn't count for muscle gain, which could offset some of the pounds lost. For example, someone could lose five pounds of fat, but gain three pounds of muscle, which would result in only a two pound weight loss on the scale.
Body Fat Lost
Body fat percentage is a more accurate way to judge weight loss because it incorporates both fat loss and muscle gain. The easiest way to measure this in a weight loss competition is to use a scale that measures body fat. You can also measure body fat using skin calipers, though there is much room for human error with this method.
Measurements of body fat percentage do vary based on the amount of water a person has in her body, so be sure to measure at the same time each week to get the most accurate results.
Pounds as a Percentage of Body Weight
When the weight loss contest participants are coming from very different starting points--for instance, if one person needs to lose 100 pounds and another only needs to lose 30--a fair way to measure weight loss is by calculating the weight lost as a percentage of the person's body weight.
For example, if someone weighs 250 pounds and loses three pounds in a week, the percentage of body weight lost is 1.2 percent. Someone who weighs 175 pounds and lost three pounds in a week lost 1.7 percent of her body weight. Even though the two people lost the same number of pounds, the second person would be the winner because she lost a larger percentage of her body weight.