Glucose vs. Ketones
A hallmark of both ancestral nutrition and a healthy metabolism is the ability to be fat-adapted, but what does this mean, exactly? This is a question I frequently get, particularly when I engage in conversation with lay-scientists who tell me to, "just count my macros, dude," which is part of it, but not the only piece.
I highly agree with counting macros, and a person who is netting the best results is paying attention to all the moving parts-macros absolutely included (macronutrients are carbs, protein, and fat-counted in a nutrition budget format where you're hitting your number of grams of each per day-sometimes using a food logging app), food choices, and also their metabolic functionality. This is where the bro-scientists and I part ways, as they often believe exclusively in the calories in vs. calories out method for metabolic functionality, not to mention copious amounts of carbohydrates to fuel workouts and lifestyles that should necessitate less.
Back to the point: A fat-adapted person is able to burn fat for energy. A fat-adapted metabolism is the optimal state for human metabolisms. A hallmark of ancestral eating, this is the way our body's evolved to function. Somewhere along the lines, we got away from that by topping ourselves off with carbohydrate gasoline in excess.
Full-disclosure: I am not anti-carb at all. I love carbs. I eat them. Not just fibrous carbs (in the form of vegetables), either. I'm talking starchy carbs. I just believe in recruiting them differently than most of the population, mainstream academia, and most low-rent science.
Why being fat-adapted is good
Fat-adapted folks are able to rely on their own body fat as an energy source. It's true-our body more easily converts carbohydrates into energy, but that efficiency doesn't equal optimal metabolic function. Fat is a secondary energy source, and a much more reliable one at that. Let's take a look at what fat burners are able to do in contrast to carb, or sugar burners.
-Are able to access their stored body fat for clean, sustainable energy throughout the day.
-Are able to run off of dietary fat (fatty food intake) for energy efficiently.
-You store less fat from your meals. Postprandial (after a meal) fat oxidation means less fat will be stored in your existing adipose a.k.a. fat tissue.
-Can train without having to carb load.
-Can train in a fasted state effectively.
-Can use their existing fat to fuel training....at least to a point. Certain, highly intense, highly glycolytic activity may necessitate a higher carbohydrate intake at some point. In an ideal world, if you're fat-adapted, and eating for exercise demands, you're running off of your own fat until you truly need the glycogen loading that carbs provide.
-Have a flexible metabolism and can toggle between energy sources. Don't worry. Increasing your fat intake doesn't mean your ability to properly utilize carbohydrates goes away-quite the opposite. Fat-adaptivity means your metabolism is flexible. Metabolic flexibility allows the fat-adapted superhuman or athlete to deplete existing glycogen stores and properly reload the glycogen stores efficiently. Like refilling an empty glass of water or reservoir. Any excess dietary fat not stored will be burned. The individual will then be able to access these new glycogen stores when needed.
-Potentially be able to handle high carb, refeed meals or days without the same consequences as a sugar-burner.
Hopefully this sheds some light on optimal metabolic functionality and how we are truly meant to run, genetically. Work can be done to override your existing metabolic machinery if it's broken.