If you are training then you will lose weight with a normal diet, and it will be far healthier.

With a restricted calorie diet, your system becomes stressed and has to compromise in some manner. Maybe your performance will soften, your endurance may suffer, maybe your immune system will revolt.

Just eat a normal diet and you will still whittle away the lard.

That's what I was worried about... the health and recovery side of the stricter diet.

You need to decide what you want to do. Low carb isn't low calorie and if you do combine them you will burn out big time. Cutting carbs but adding fat will allow you to keep the calories at a safe level but you still need to adjust training intensity to aerobic to suit that. One you have done that for a couple of week you can start to trickle carbs back in before key sessions to help reach the higher intensity while keeping the carbs lower. No need to cut them out entirely. Also best to target the natural carbs in sweet potatoes and rice rather than sugary carbs like gels and bread. No reason you can't bring the gels back in on raceday to give you a massive boost though.

Based on some experimentation and what I have seen, when you cut carbs your ability to recovery quickly will suffer. This leaves you with two options. You can keep all of workouts easy and try a low calorie/carb diet or you can target a higher training load and not cut back so much. The first option definitely presents greater risk in terms of injury or burnout. The second option can still work quite well if your meals are healthy. At a minimum I would only experiment with the first option for a few weeks before moving to the second approach. I will say that simple things such as cutting out bread can have a huge impact on weight loss.

Look at your diet closely. For example I was shocked recently when I realised just how much milk I drink-1 litre per day of full cream milk with equals around 650 calories! By 7 days is 4550 calories that I didn't fully realise I was ingesting...

It's weird you recovered worse. I and many others have experienced the polar opposite. Little to no doms, no muscle tightness and much speedier recovery between sessions which resulted in being able to do much more. Though I was cycling through (good) carbs when needed but in much smaller amounts than society makes us believe we need.

I do think though it's more to do with eliminating sugar from the diet than anything.

Just switching to low carb will have you eating less calories, because for one fiber and protein have a higher TEF rate. So start there, if no change in a 6 weeks drop the cals down

I trained for an Ironman last year (4th one) and didn't drop an ounce. At my age (44) my body doesn't drop weight like it did in my 30's. My wife actually gained weight while IM training and was told it's fairly normal.

Just my n=1. Or 2.