[rnovak]

Now, here's my opinion, and I know it might be wrong. Anyone, please feel free to correct me, but:

Everything I've read suggests that 1lb muscle requires about 50 calories a day to maintain.

The workout programs these contestants are using are focused solely on cardio, or very heavily focused on cardio.

If as part of the 239lb weight loss, Mr Cahill lost 8lbs-10lbs of muscle (and never regained it), there's your entire 400-500 calorie difference right there.

Like I said, I could totally be wrong, but over the last year I lost 93lbs (as of today), but my measured BMR is actually higher than it should be (and higher than it was when I started). I attribute that difference to my focus on lifting weights more than cardio.

[rayiner]

Muscle burning 50 calories a day is a myth. Gaining 20 pounds of muscle adds 80-100 calories to your RMR for a typical person: http://articles.latimes.com/2011/may/16/health/la-he-fitness....

[itchyouch]

Yep. It's muscle recovery that is very calorically expensive. Those who have lifted or lift can probably attest to that crazy post workout appetite.

[rnovak]

Thanks for the correction. I will point out that the article does indicate that there is some type of difference, so I would still think that such a loss would have some sort of impact (though obviously not ~400-500 calories worth).

[TearsInTheRain]

They mentioned that they have a lower metabolic rate than someone of the same size. I doubt they have less muscle than the average person at their weight

[rnovak]

From his picture from the biggest loser, he looks a lot different at 191lbs and 5'11" than I do at 195lbs and 5'11".

With as much cardio as they did, with as little as they ate, I can easily see them having a different body composition than someone else of their height/weight.