You do realise a lot of nutritionists do not even have university degrees, right? They understand nutrition on a very basic level and they don't have a proper understanding of the energetics of exercise. Most of them are obsessed with getting their clients quick results so they gain conviction in their plans and most of these people will end up putting the weight back on. Pointing the finger at fruit, is completely the wrong attitude to take. The issue isn't fruit.
A high fat, low carb diet will be unsustainable for the far majority of people, and I guarantee you, that if you upped your carbs and lowered your fat intake you would see better results. Glucose is your quickest source of energy. If you want t resynthesise ATP as quickly as possible you need more carbs.
The fact is everybody should be doing at least an hour of moderate intensity exercise a day (or half an hour of high intensity exercise- note unless you're obese or really old walking does not count).
I hope for your sake, you can sustain yourself with low carbs and continue to make gains. However, the fact is it's completely wrong for the majority of people and it will backfire for most of them. For every person who comes out saying low-carb is good practice there are dozens of more credible studies proving that they're wrong.
Look at the longest living people on Earth, all the blue zones, they not only live longer than people in the west but they age a lot healthier. The Okinawans the longest living ones traditional diet relies heavily on vegetables, wholegrains and fruit.
You got a six pack after two years of training? I did it in seven months I went from being 160 cm and over 80 kg, to being under 60kg and I was benching over 60kg (for a girl that' good) too. I ate a lot of fruit. Post workout I would eat five servings of fruit and a tuna sandwich on wholemeal bread.
Lo carb diets are built to get quick results, that's about it.