No you need to eat substantial calories especially protein to build muscle
you’re absolutely right I’ve a degree in health science,exercise physiology and nutrition and wouldn’t even dream of giving anyone advice
Also if you’re in a constant deficit it eats in to muscle AND fat! I think that’s why people spend some time bulking ie eating more to maintain and then cutting(Restricting cals) to lose fat especially bodybuilders
Do you know what annoys me? Sorry I’m on a rant
but as I mentioned my degree it’s a 4 year degree learning about the mechanics of food(nutrition/biochemistry) exercise prescription for all types of people(men/pregnant women/older adults/kids) and anatomy & physiology of the human body focusing on all aspects of fitness and health but I am not qualified as a PT after it, I would have to do an actual add on in personal training, whereas this one just did a 6 week course and she can’t even cook or have a somewhat healthy relationship with food and exercise