I am a personal trainer certified through ACSM, a martial arts instructor and I do have a bachelors degree in movement and exercise science.
Whew, that being said, I am not a certified nutritionist, I only studied sports nutrition. Bodybuilding is a pretty broad term these days. Technically anyone who lifts weights to gain muscle could be classified as a bodybuilder. It ranges from basic health increase, sport performance, pure aesthetics and bodybuilding competitions.
The basics for all of it is the same, its only when you start to become an advanced lifter that things start to really get specific. As long as you have a good strength training program, and follow standard progressive resistance, safety, etc you will be fine.
As for nutrition, it boils down to a few factors. kcals in vs. kcals out, and an adequate amount of protein. So, what you need to know, is if 1.4’s macros fit within your range. Lets do some math.
157 lbs is 71kg, you want to keep your protein intake 1-2x your weight in kg. Anymore than 2x and its converted into sugars and fats, any less, and your can’t build enough muscle. So your protein range is 71-142grams of protein a day. 1.4 has 84g of protein per day. Now, if you add in a standard 25g afterwork shake your sitting at 104g, which is just fine.
Now, that is a very simplified breakdown, to get more specific we could use your bodyfat % to figure out your lean mass and bone mass, etc. Eventually you want to decrease/increase your protein to match a desired weight level within a range limit as well.
The second thing you need to calculate is daily expenditure. 1.4 has about 2000 kcals. Your specific daily expenditure can be learned with online calculators. The formula takes into account gender, weight, height, activity level to give you a basic idea of how much you need to eat. For basic bodybuilding, and to lower bodyfat % with increase muscle you want a “slight” calorie deficit with adequate protein. Depending on if your doing cardio (and how much)(and you prolly should) and how much your lifting, will increase your daily kcal expenditure. At your weight and age, depending on how much your exercise that can go all the way up to 2800-3000 calories a day.
The calories from a protein shake (post workout) plus 1.4 would be around 2150, maybe 2200. If your slightly to moderately active you will burn on average 2200-2400 kcals a day. So if you go 100% 1.4, you would prolly be right on the money.