Whey, Milk, Insulin and Sleep

A recent nutrition item on milk by Jerry Brainum (“Milk, Estrogen, IGF-1 and Insulin,” August ’09) got me thinking. When people can’t sleep, they often drink milk. That’s because the tryptophan sparks serotonin release, which promotes relaxation. According to Brainum’s article, however, milk spikes insulin—and that can be a problem.

Insulin is an antagonist to growth hormone, and you get your most prominent GH surge a few hours into sleep. So if you drink milk before bed, you might suppress a lot of your GH output. That’s not good from a health standpoint, not to mention a fat-burning one.

Remember, insulin turns off fat burning, so milk before bed is not a good idea for those trying to get or stay lean. Even if you’re not a bodybuilder, you want to maximize GH for a number of health reasons, including antiaging benefits.

Along those same lines, you don’t want to drink straight whey protein before bed either. The latest research shows that whey, like milk, spikes insulin.

I can hear the bodybuilders screaming: “But I need some muscle-building aminos before bed!” No problem: Drink a pure casein or whey-and-casein-combo shake. Casein curdles in the stomach and slows digestion, blunting insulin release. Plus, you get a trickle-feed of amino acids for many hours as it slowly digests.

Putting two and two together, you may be thinking that straight-whey-protein shakes during the day spike insulin too. Correct. If you’re purely on a mass-building mission, that’s not a big problem—insulin promotes anabolism; however, if you’re trying to burn bodyfat at the same time, it’s a very big problem. Remember, insulin turns off fat burning, so if you have straight whey throughout the day, you’re burning very little bodyfat. Once again, a casein-and-whey protein array is a better choice if you’re trying to get lean because insulin release is minimal.

Of course, after a workout you want an insulin spike to drive aminos and glycogen into your muscle cells. That’s when you always want a straight-whey shake—and don’t forget to add some creatine to shuttle that important compound into the muscles as well.