muscle building program
Training programs for building muscle are the same regardless of whether or not you are cutting. Cutting training may need to deal with recovery a bit more, but overall the basic principles are the same.
Muscle building requires going on a bulk
Not necessarily. Muscle building requires stimulus, energy and protein. Eating in a caloric surplus makes it easier to get the last two. Being overweight can ensure the energy part.
There are four types of people who can gain muscle while eating on a deficit:
- Those who are new to lifting.
- Those who are overweight.
- Those who are on PEDs.
- Those who are some combination of 1-3.
The body scan machine said I have 30% body fat and I read that for such people, the best bet is to focus on cutting first
I would agree with this statement. However there are other things to consider like how easy it is to adhere to the plan. Maintenance and slight deficits are easier to follow. Especially if you're building and learning new habits like calorie/macro counting and training.
he told me that when I put on muscle, my metabolic rate will increase and it will raise my caloric expenditure even when I am not actively training
That's technically true, but it's not very much. It's about on average 10 calories per LB or 5 calories per KG. So let's say you had a great year and managed to add a whopping 20 lbs (10KG) of lean muscle, your TDEE would have increased 200 calories a day.
Hence, he said muscle building is a suitable option for me in my current state.
I believe this statement is true. Not just for weight loss, but for overall health, lifestyle, and longevity.
I personally in that position would start at a maintenance plan or maybe even slightly under (around 250 calories).
Although I can't speak for your trainer. That may be what (s)he has planned but is starting with a starting point just to test and assess how your body reacts. Hopefully, they will adjust accordingly to meet your goals.