Macronutrients

Probably about the deepest level we provide and answer about it is there is probably some level of hormonal difference between dieting and a surplus that regulate protein synthesis and protein breakdown. Given level of existing muscle, severity of deficit, and actual amount of existing adipose (an obese individual may make some gains while losing fat), I would guess leptin is at least one of the hormones involved.
There is a lot of coordinating conditions needed to produce muscle hypertrophy and it seems calorie intake is one of the limiters.

An excess of carbs isn't truly necessary for bulking, it just tends to be the preferred macro to increase for a few reasons. One is that carbohydrates provide fuel, so it seems reasonable to make sure there is always fuel available to maintain workout performance. Another is that carbs will cause rises in insulin, which itself is an anabolic hormone.
There is some evidence to suggest keeping protein high while gaining is good at keep fat gain during a bulk lower.

sijomial wrote: »

SCoil123 wrote: »

Here is my simplest explanation-

You need materials to build anything, this includes muscle. You couldn’t add another room to a house without buying new materials right? Hammering on the existing walls all day long without the materials wouldn’t build anything new. It’s similar with building muscle mass. Your body already uses your maintenance calories (energy) to run what you have, like the existing house in my example. To build and gain you need to give it the extra materials (calories) to do that.

Over-simplified and poor analogy IMHO.
In the case of energy people have loads of "materials" on site already - it doesn't have to brought in every day.
Ignoring glycogen a male at 200lbs and with an athletic build of 15% bodyfat has 105,000 cals of "materials".

Your "building" also isn't static, you are constantly breaking down, rebuilding and building most tissues including muscle in the body all the time, that doesn't stop just because you are in a deficit. The size of that deficit definitely matters though.

Of course a deficit is making conditions far more difficult for "significant" muscle growth but that's a million miles away from a surplus being an absolute requirement. It's a continuum not a mode switch. Where an individual sits on the continuum is very personal.

You’re welcome to your opinion. My goal was to be as simple as possible in the analogy so calling it over simplified is fine.

Too often people come here thinking they will/can gain muscle and bulk working out in a deficit. Chances are extremely high they will not. There are rare exceptions to everything.

I personally find it best when starting any journey to keep things as simple as possible so in this case for me that means - deficit=weight loss including fat, water weight, and some muscle, while surplus=weight gain of both muscle and fat. You activities and macro splits will determine how much of each you lose or gain but it really is that simple 99.9% of the time