Why we recommend Casein Custard at night time.
When tucking into bed at night, you're about to embark on a six to eight hour journey of rest and repair. After all, it's been a long day. However, during this time you aren't feeding the body. (We call this the post-absorptive period).
If you haven't heard of this post-absorptive period before… let me explain.
Throughout the day, the first hour or two after eating is referred to as the post-prandial period. During this time, the body digests and absorbs nutrients. When you eat and even during the post-prandial period, the body's maintenance needs for blood glucose and energy are met. At this time it begins to synthesise proteins and glycogen in the liver and muscle.
Once this period is over, the post-absorptive period sets in. After the absorption of the nutrients from your last meal is complete and the nutrients in the blood have been delivered, the body begins using those stored nutrients for energy. Then, in order to maintain blood glucose and tissue metabolism, the liver and muscle start metabolising and sending glucose and amino acids out into the blood.
So after an overnight fast and a long post-absorptive period, some of you muscle glycogen and muscle protein will have been depleted. So during your overnight fast, muscle protein breakdown exceeds muscle protein synthesis.
To Inhibit protein breakdown we only need small increases in blood amino-acid levels (25-50% above fasted baseline). However, these small increases must be prolonged (4-5 hours) in order to realise this inhibition of protein breakdown. In this situation, a slow-digesting protein like casein is necessary.
Casein protein intake (30g) produces moderate but prolonged hyperaminoacidemia. After two hours, blood amino acids are elevated by about 32% and after four hours by about 35%. After seven hours, blood amino acids are still elevated. This is ideal for prevention of protein breakdown but does nothing for protein synthesis.