Just wondering, what is the source of these suggestions?

Based on my research, everyone's body is different and we need different practices for sustaining health.

ONE - concerning meals: for some intermittent fasting works, One meal a day is necessary, or 5 or meals per day are best.

When I wanted to put on 50 lbs of muscle, I was eating 4000 cals per meal, 5 times a day. Food was part of my daily workout. Trust me, it is a work out to eat that much. Just read about Chris Evans or Chris Hemsworth's workouts.

TWO - Based on my research this is reliable. Also, lemon water or lemon-cayenne pepper-honey water. pedialyte. Rehydrating is important during exercising.

Also, remember to rehydrate after working out. Drinking or eating a mixture of Fats, carbos, and protein within 30 minutes after working out can replenish glycogen.

THREE - What is the justification for this?
Juice can have a lot of sugar so I would be careful about drinking this much juice. I like the question: Can you eat that much fruit?