I think it is hard to make fitness gains while on a big calorie deficit, but the less fit and more overweight you are the easier it is. I.e. Somebody who is at 15% bodyfat and has been training 10 hours/week for a couple of years and is trying to get down to 12% BF probably shouldn’t expect any power gains while doing so, and may even lose a few watts. For you at 30% BF trying to get to ~23% BF it should be easier. Very hard to lose only fat though, there’s nearly always a bit of muscle loss along the way.
Re the advice about fuelling workouts the higher the intensity the more carbs you need and if your muscles don’t have enough glycogen available you either won’t be able to complete the workout, the quality will suffer, and/or your recovery will suffer. So fuel appropriately to ensure you can do a quality workout. You also don’t want to finish the ride on empty and then pig out!
“Appropriate” depends on workout length, intensity and when you last ate. My rough and ready approach is:
- Assume I have 1500 calories glycogen available if I’ve eaten recently
- Aim to finish with at least ~1000 calories of glycogen left so I’m not running empty or tempted to overeat after
- Figure about a third of calories come from carbs for recovery and endurance workouts, half for tempo and sweetspot, two thirds for threshold and above (this isn’t spot on but it’s easy to figure and close enough for my purposes)
So for something like Pettit, it’s 750 cals total, 250 from carbs, so if I’ve eaten recently I don’t need to eat during the ride, if I’ve just got up and am training before breakfast I’ll have a few calories to get the metabolism going. For a long SS session like Wright Peak -2, it’s 1800 calories, 900 from carbs, so I should be aiming to eat 4-500 calories during the ride. For a 1 hour VO2 workout like Baird +2 it’s 900 calories, 600 from carbs, so borderline as to whether I need to fuel during the workout if I’ve eaten beforehand, but I also need all the help I can get on those workouts so I’ll typically have a small sugar hit like a date or 2, a bit of dried fruit or a few Haribo as a reward after each set.