Question of the Week: Do Milk and Cookies Benefit Your Beddy Bye?

Dear Real Fitness Nerd - 

I heard that there's a new study out validating the benefits of carbs before bed to help you sleep. Does this mean I get to put Thin Mints back on my bedtime menu?

Sincerely,

Sleepy and Snacky in Saskatchewan

You so badly want me to say yes, don't you, Sleepy?  Because I am a kind and generous Fitness Nerd, that's exactly what I'll do. The answer is YES!*

That's it for today's blog. Thanks for reading... oh wait. It looks like an asterisk popped up next to that "YES!" Who put that there? I didn't type that! Looks like I'll have to go talk to legal. Please hold...

(play soothing waiting room music here)

Okay, I'm back. I checked with the Real Fitness Nerd Legal Department and it turns out, the answer is still YES*, but only provided you eat it FOUR HOURS before your head hits the pillow. You'll also need to eat high-glycemic carbs with little fiber, protein, and fat. And you need to make sure that your snack contains an amino acid called tryptophan. FURTHERMORE, you need to be aware of the fact that this sort of snack will generally promote type two diabetes and heart issues, unless timed when your blood sugar and glycogen are extremely low, like after a workout.

Whew. Sort of takes the fun out of it, huh? Damn Legal Department.

In case you're curious, the reason this type of snack works is due primarily to that tryptophan, which the body uses to create serotonin, a neurotransmitter that slows your brain down, promoting restfulness. But for tryptophan to work like this, it needs to cross the blood brain barrier, which means it needs to have easy, quick access to your brain. High-glycemic (fast-absorbing) carbs help this process, but other amino acids (proteins) do not. This is why the myth that Thanksgiving turkey makes you sleepy was debunked recently. Turkey may contain tryptophan (as do other birds), but all the other protein and fat that comes with it means it doesn't really get to your brain.

And why the four hour rule? I'm not 100% sure, but my guess is that this is how long it takes for the serotonin to kick in. If you don't believe me, here's a study out of Australia confirming it. They fed the subjects rice (a tryptophan-containing carb) at various times before bed, finding that the 4-hour folks fell asleep faster than the 1-hour folks.

Frankly, this is a good thing, considering eating right before bed also messes with your sleep cycles, meaning you may be asleep after that midnight snack, but you're not going through proper REM cycles, so you're not getting proper rest. I could keep going about how this, in turn, can promote over-eating and how a recent study found that sleep-deprived teenagers tend to crave carbs, but I've thrown enough science at you for one day, so instead, I'll share with you this weird, Japanese television show where they mess with sleeping people:



*some conditions apply.