As noted, fat adaptation is not an on/off switch. It’s a gradual process wherein your utilization of fatty acids and ketones becomes more in synch with lipolsysis and ketogenesis. Many folks will cite all sorts of subjective criteria that they ‘knew they were fat adapted’. The problem is that not everyone experiences the same things. Subjective criteria involve a lot of wishful expectations and wish fulfillment. For instance, I’ve been keto for 3+ years and I never experienced what I would define as a noticeable increase in energy. I’ve been fairly active all my life and that did not change when I went keto. I have no idea what people mean when they claim ‘brain fog’ was replaced by ‘mental clarity’. I have never experienced what I would define as ‘brain fog’ and have been all my life and remain ‘mentally clear’. So what exactly do those things mean? They mean nothing to me. They might mean nothing to you.
A more serious problem, I think, is that newbies read other peoples’ descriptions of what they claim to have experienced, don’t experience anything like it and conclude, erroneously, that there’s something wrong. We get repeated pleas of ‘what’s wrong with me?’ or ‘keto doesn’t work?’ or ‘what am I doing wrong?’ or ‘why has my weight loss stalled?’. These not only from newbies who have been keto for a few days, a couple weeks or a couple months, but even from folks who have been at it for 6 months or longer and are still awaiting the metabolic light switch to flip on.
My advice is simply this. Eat sub-20 grams of carbs per day, the fewer the better. Stay in ketosis consistently for at least the first year. No ‘cheat meals’ or ‘cheat days’ or ‘days off’. No alcohol. Eliminate all sweeteners. You don’t need ‘sweet’ and the sooner you lose it the better. If you do that, you are 99.9% sure to be utilizing fatty acids and ketones efficiently. Will you get ‘better fat adapted’ after that. Yes, you will. But the first year will result in the biggest gains in efficiency.
One other thing. Keto is a normalization process, not a crash diet. Every one of us had at least some metabolic damage prior to keto. The more damage the longer it takes to repair and attain the normal range of metabolic function. SAD has damaged some so badly they will never attain complete normality, but they will get better and have a much healthier life for it. Unless you are severely overweight, or have had medical tests done for one or another reason, you don’t know how damaged your metabolism is and how long keto is going to take fixing it. So don’t compare yourself to others.
Do the best you can in the assurance that doing so will enable you to live healthier, live longer and live a more satisfying life. Say thank you to these guys for giving us a forum to discuss it.