Insulin. Guns is right. If you eat a big meal on Thanksgiving day, it is not the tryptophan in the turkey that makes you sleepy. It is the consumption of high calorie high carb meal that causes your body to dump insulin.

Anyone who has done slin knows that you hit that shot PWO and all of the sudden feel a little slower and ready to EAT then want to take a nap.

If you want max alertness have you done keto diet?

1st you are not hungry, second you do not get insulin spikes that cause brain fog and sleepiness. This is one prob. Obviously getting rid of waste is big. I did the same not long ago for a colonoscopy.

The Science Behind the Mental Clarity Diet | by Andrew Zaleski | Elemental