Yes, they demonstrably do. I have no will power which is how I wound up 125lbs overweight. So... No. I'm not eating leafy greens until after I'm done loosing enough fat to say I'm not fat anymore. At least another 25lbs, maybe even another 50 to go. All meat until then (though, an occasional meal with the family is fine).  

 If you hodl you have will power. 

 Being addicted to carbs and hodling BTC are not the same.