I was wondering if I can maintain my mass or even gain mass while on intermittent fasting, all while being healthier while doing so. I will be doing the 16/8 diet.
Maintaining or gaining is all a function of eating at or above maintenance calories for your body, regardless if you eat those across the day as three meals or in a smaller window. If you need 2,500 calories to maintain weight eating that 2,500 calories in 8 hours will still maintain.
Now depending on the body and method condensing that many calories into a smaller window can be challenging, but certainly doable with good nutrient dense foods.