How many surplus calories should I be eating to gain lean muscle only & 0% fat?
As far as 0% fat gain goes?
It’s going to be highly unlikely that you can. Although, there are ways and means to minimise the gaining of fat during periods of caloric surplus.
Your approach here should be a gradual one, as the faster you gain weight, the greater the likelihood that a higher percentage of that weight gain will be fat. And the faster you lose it, the higher the chance that the lion’s share of weight that you lose will be muscle. The body is rather tetchy when it comes to maintaining its homeostasis.
But let’s go with some reasonable observations and suggestions:
- 1 kg of muscle is equivalent to roughly 4000 kcal of extra food (not exactly, because there’s a water component to lean muscle mass and respiration, metabolism and so on, but good enough for us).
- 1 kg of fat will set you back about 9000 kcal. So, if you want to gain fat, eat lots.
- Take a larger portion of your calories in as protein and essential fats and less as carbohydrate.
- From over 40 years experience, gaining anything over 1/2 kg–1 kg on a weekly basis will give you a higher % gain in fat than muscle added.
Let’s say that you are determined to go balls out and gain 1 kg per week. Adding an extra 4000 kcal/week is a good number to start with. Remember, this is going to have to be 4000 kcal per week surplus. In particular, you’ll need to figure out what you need as an individual for maintenance purposes and add this surplus to the number of calories that you’re currently spending. If you need a parsing as far as the macros go, something like 40%PRO, 40%FAT, 20%CHO should work nicely.
For example, most people will divide the surplus over a 7-day period (between 500–600 kcal/day) which is fine. But it doesn’t have to be evenly divided.
The key to action here is to get the total of your maintenance & surplus calories in over the period of a week, check your progress and make adjustments on the basis of the results.