No. Can Fat Adaptation Make You Faster?
TLDR: Don’t get “fat-adapted” via your diet. Do it via training more. Fat adaptation caused by limiting carb intake is a surefire way to reduce performance.
Low carbohydrate, high fat diet impairs exercise economy and negates the performance benefit from intensified training in elite race walkers - PMC (many others like this)
Even chronically low-carb folks can handle 90g/hr, in the vast majority of cases and I suspect up to maybe 100g/hr. Just need to nail sugar ratios to close 1:1 gluc:fruc.
Even averaging 150W merits maximizing carb intake for optimal performance (lowest RPE and HR for a given power). Thus, the vast majority of riders reading here will benefit from maximum carb intake rates.
The benefits from maximizing carb intake will probably be greater for those who sustain larger power outputs because they’re effectively running a bigger carb deficit throughout their training sessions.