Not a source I'd consider to be one of the top ones, but the content is correct. You can find Phinney and Volek YouTube videos about their studies of elite athletes and diet.
One of the more interesting bits is about "the wall" that people who run long distances (for example) hit.
You can only store so much energy from carb intake, to use when you exercise (or move about, fidget, whatever). If you do the
@Denny Crane diet (ketogenic diet), you burn fat stores for energy for exercise. The difference is something like 2000 kcal max for carbs, and something like 40,000 kcal max from body fat.
You cannot be fat burning adapted AND carb up.
http://fitfluential.com/2016/11/ketogenic-diet-for-endurance-athletes/
So what is the ketogenic diet? A ketogenic diet is a high fat, moderate protein and very low carb diet. It is set up (depending on your goals) with your calories coming from approximately 75% fat, 20% protein, and 5% carbs. This can be tweaked depending on your activity level or what feels right for your body. The goal of eating high fat and low carbs is to bring your body to a state of ketosis. Ketosis is when your body reaches a state where it is deprived of glycogen (which is energy that comes from carbs) and it begins burning fat for energy instead.
Since glucose is only stored in limited amounts in the body, you have just that – limited amounts. When the glucose is all burned out, you’ll “hit a wall” or begin to fatigue.
When depending on ketones and fat as fuel, you have a much larger supply of energy, which can effectively prevent you from hitting that wall. But getting to this state of ketosis doesn’t happen in a day – it can take about 3 to 5 weeks to adapt. To become keto-adapted requires a lot of discipline, so you’ll have to take a rain check on those cheat meals for a while.
Dave Scott, a six-time IRONMAN® world champion and a big proponent of the ketogenic diet who shares
tips here, shares, “As I’ve become keto adapted, I’ve noticed that my hunger signals are more in check, likely as a result of no longer having the insulin surges that follow a carbohydrate-rich meal or snack. I feel that I have a better pulse on when I’m really hungry compared to my previous way of eating in which I always felt hungry and my satiety signal was never really, well, satisfied.”
