The cultural resistance against reducing dietary intake of carbohydrates is palpable. Despite copious cogent arguments pointing out how humans improve at everything when they restrict carbohydrate intake long enough, people can't seem to help themselves or commit to the change long enough to see how profound it is. Fortunately, researchers at the Ohio State University have put to rest the last languishing excuse that people have for eating high carb diets: carbs improve endurance performance. Wrong.
Though we've known it can take a while to become great at fat-preferential metabolism (in this study, their low-bound was 6 months of keto-adapted dieting, and the average was 20 months!), this study proved that all of the physiological excuses typically offered to stick with carbs are bogus. Elite endurance athletes who eat 10% or less of their calories sources from carbohydrates had no diminishment of glycogen stores, glycogen replenishment, or glycogen metabolism in any measurable or meaningful way. Surprise, surprise, their body fat usage was twice as high (or more) than the high carb group.
Summary takeaway: carbohydrates are not needed to fuel performance, even when it is endurance activity. Thus, the layperson adult has NO NEED FOR CARBOHYDRATES. Strength and power athletes may have cause for higher intake than 10%, but, again, not shortly before performance, as it will only inhibit the use of fatty acids and ketone fuels. For recovery, after activity, it could be warranted. But this study even showed that glycogen replete rates were no different in the carb-restricted group.