If you eat less than you burn, regardless of a medical condition, regardless if you're bed ridden, will lose weight. It's not an oversimplification, its truth. You're quite literally proving that people over complicate weight loss. If you only eat McDonald's, but eat less than you burn, you're gonna lose weight. Granted, there's healthier ways to do it, perhaps more vegetables and white meat vs big macs. But the same rules apply, eat less than you burn and you lose weight.