-I know you directed your question towards Dan, but, I'll give you my 2 cents even though you didn't ask for it . T3 levels are compromised when one is on a diet for a elongated period of time. Your body thinks you're starving and consequently slows your metabolism/T3 levels. This is often the reason any diet quickly reaches a 'plateau'. The CKD combats this problem by the overloading of carbohydrates and calories during the carb-up. To sum it up- before your body starts to REALLY slow your metabolism, T3 levels, etc. . The carb-up 'jump-starts' everything right back up to par.