Fat-adaptation is the normal, preferred metabolic state and the best and optimal source of energy! To understand if you are fat adapted or not, you need to understand what being a sugar-dependent person feels like.
A sugar-burner can’t effectively access stored fat for energy. What that means is an inability for skeletal muscle to oxidise fat, and that means the sugar burner runs out of energy quickly if they have not had their sugar fix!
A sugar-burner can’t even effectively access dietary fat for energy. As a result, more dietary fat is stored than burned. Unfortunately for them, they’re likely to end up gaining lots of body fat.
A sugar-burner will burn through glycogen fairly quickly during exercise. Depending on the nature of the physical activity, glycogen burning could be perfectly desirable and expected, but it runs out quickly and if you’re able to power your efforts with fat for as long as possible, that gives you more glycogen – so sugar-burners waste their glycogen on efforts that fat should be able to power.
Being fat-adapted, then, looks and feels a little bit like the opposite of all that:
A fat adapted burner can effectively burn stored fat for energy throughout the day. If you can handle missing meals and are able to go hours without getting ravenous and cranky (or craving carbs), you’re likely fat-adapted.
A fat adapted burner is able to effectively oxidise dietary fat for energy. If you’re adapted, your post-prandial fat oxidation will be increased, and less dietary fat will be stored in adipose tissue.
A fat adapted burner has plenty of accessible energy on hand, even if he or she is lean. If you’re adapted, the genes associated with lipid metabolism will be upregulated in your skeletal muscles. You will essentially reprogram your body.
if you can handle exercising without having to carb-load, you’re probably fat-adapted. If you can workout effectively in a fasted state, you’re fat-adapted.
Ultimately, fat-adaption means metabolic flexibility. It means that a fat adapted burner will be able to handle some carbs along with some fat. A fat-burning beast will be able to empty glycogen stores through intense exercise, refill those stores, burn whatever dietary fat isn’t stored, and then easily access and oxidize the fat that is stored when it’s needed. Once the fat-burning machinery has been established and programmed, you should be able to effortlessly switch between fuel sources as needed.
To find out if you’re fat-adapted, the most effective way is to ask yourself a few basic questions:
- Can you go three hours without eating? Is skipping a meal an exercise in futility and misery?
- Do you enjoy steady, even energy throughout the day? Are midday naps pleasurable indulgences, rather than necessary staples?
- Can you exercise without carb-loading?
- Have the headaches and brain fuzziness passed?
Yes? Then you’re probably fat-adapted. Welcome to normal human metabolism!
A quick note about ketosis:
Fat-adaption does not necessarily mean ketosis. Ketosis is ketosis. Fat-adaption describes the ability to burn both fat directly via beta-oxidation and glucose via glycolysis, while ketosis describes the use of fat-derived ketone bodies by tissues (like parts of the brain) that normally use glucose.