Calories. I personally recommend when starting not to restrict calories. Instead allow yourself to settle comfortably into the time restriction. You can adjust food later.
I’m not suggesting changing your diet if you’re avoiding things like sugar, but I wouldn’t restrict your calories if it’s detrimental to your success.
I had a 3 week transition period. Weak, tired, exhausted at any little thing. I only stuck with it due to pressing health issues. Suddenly, week 3, I was awake, energetic, and fine. I realized I had gone through a transition period. Maybe give it more time.
hard to say why you’re feeling cravings for sugar but if it makes you feel better i think we all feel them every now and then. id suggest indulge but control it - like have a snickers, or eat 40g of jellybeans or something like that. and then stop.
because remember bro - this is for the longterm. and only way to do longterm is not having the feeling you are giving up/sacrificing anything.
What are you eating during your window? The first couple of weeks my calories really dropped as I was used to picking through throughout the day and I battled to sit down and eat full meals. I tracked out of curiosity one day and I was at 900, which explained by my workouts were suffering. I just started paying more attention to my meals.
My biggest issue is that I work out a fair bit and I’m never hungry after, especially if I have a protein shake (unflavored, mixed with water). I’m working on shifting my workouts to earlier in the day.
16:8 is really just skipping breakfast. You should still be able to hit your nutrition and calorie goals in 8 hours given that for half the 16 you’re asleep.
Introduce more carbs perhaps. Your body needs a fuel source and your not doing keto so your body isn’t using fat it’s using carbs but your on a low carb diet. I would introduce a moderate amount of healthy carbs.
Also you may be in too big a calorie deficit